Evaluation of the neurotoxic/neuroprotective role of organoselenides using differentiated human neuroblastoma SH-SY5Y cell line challenged with 6-hydroxydopamine

Undifferentiated versus retinoic acid-differentiated SH-SY5Y cells in investigation of markers of neural function in toxicological research

The SH-SY5Y human neuroblastoma cell line is a standard in vitro experimental model of neuronal-like cells used in neuroscience and toxicological research. These cells can be differentiated into mature neurons, most commonly using retinoic acid (RA). Despite differences in characteristics, both undifferentiated and differentiated SH-SY5Y cells are used in research. However, due to uncertainties regarding the expression of specific markers of neural function in each culture, there is no definite conclusion on which culture is better suited for (neuro)toxicological and/or neuroscience investigations. To address this dilemma, we investigated the basal expression/activity of the key elements of acetylcholine, dopamine, serotonin, and GABA neurotransmitter pathways, along with the elements involved in exocytosis of neurotransmitters, and neuron electrophysiological activity in undifferentiated and in RA-differentiated SH-SY5Y cells using a six-day differentiation protocol. Our findings revealed that both SH-SY5Y cell types are functionally active. While undifferentiated SH-SY5Y cells exhibited greater multipotency in the expression of tested markers, most of those markers expressed in both cell types showed higher expression levels in RA-differentiated SH-SY5Y cells. Our results suggest that the six-day differentiation protocol with RA induces maturation, but not differentiation of the cells into specific neuron phenotype. The greater multipotency of undifferentiated cells in neural markers expression, together with their higher sensitivity to xenobiotic exposure and more simple cultivation protocols, make them a better candidate for high throughput toxicological screenings. Differentiated neurons are better suited for neuroscience researches that require higher expression of more specific neural markers and the specific types of neural cells.

Investigating the Therapeutic Property of Galium verum L. (GV) for MSG induced Audiogenic Epilepsy (AEs) and Neuroprotection through In-Silico and In-Vitro Analysis

BACKGROUND

Audiogenic Epilepsy (AEs) is a subtype of epileptic seizure that is generally caused by high-intensity sounds. A large number of traditional medicines has been explored in this lieu where our study chased Galium verum L. (Rubiaceae), an herbal plant which is commonly known as Lady's Bedstraw, that contains a highly rich chemical composition including flavonoids (Hispidulin, Quercetin, and Kaempferol), and phenolic acids (chlorogenic acid, caftaric acid, and gallic acid). G verum is well known for its antioxidant, neuroprotective, and anti-inflammatory properties. Recently, the unique role of Adhesion G Protein- Coupled Receptor V1 (ADGRV1) protein in the progression of audiogenic epilepsy has been explored.

AIMS AND OBJECTIVES

This study aimed to examine the potent phytoconstituents of the hydroalcoholic extract of G. verum L. (HEGV) using analytical techniques. Additionally, our study sought to evaluate the antioxidant, neuroprotective, anti-inflammatory properties, and antiepileptic potency of HEGV by targeting ADGRV1 via in silico and in vitro analyses using SHSY5Y cells.

METHODS

HPLC and LC-MS techniques were employed to identify the flavonoids, iridoids, and phenolic acid derivatives present in HEGV. DPPH (2,2-diphenyl-1-picrylhydrazyl), nitric oxide (NO), and hydroxyl (OH) radical scavenging assays were performed to confirm the antioxidant potential of the extract. Additionally, in silico molecular docking and molecular dynamic studies were performed using AutoDock Vina software to analyze the possible interactions between crucial phytoconstituents of HEGV and ADGRV1, followed by cell line analysis. In the in vitro analysis, antioxidant, neuroprotective, and anti-inflammatory properties were assessed via cell viability assay, IL, GABA, and glutamate estimation.

RESULTS

LC-MS and HPLC analyses revealed high concentrations of hispidulin, a major flavonoid found in HEGV. HEGV exhibited moderate-to-high free radical-scavenging activities comparable to those of ascorbic acid. Docking analysis demonstrated that hispidulin has a stronger binding affinity with ADGRV1 (Vina score = -8.6 kcal/mol) than other compounds. Furthermore, cell line analysis revealed that the MSG exacerbates the neurodegeneration and neuroinflammation, whereas, HEGV and Hispidulin both possess neuroprotective, antioxidant, and antiepileptic activities.

CONCLUSION

HEGV and Hispidulin proved to be promising candidates for treating audiogenic epilepsy by modulating ADGRV1.

A Water-Soluble Multifunctional Probe for Colorimetric Copper Sensing, Lysosome Labelling and Live-Cell Imaging

We report a water-soluble fluorescence and colorimetric copper probe (LysoBC1); this system can also serve for lysosome labeling and for the dynamic tracking of Cu2+ in living cells. The sensing mechanism takes advantage of the synergic action by the following three components: i) a lysosome targeting unit, ii) the spirolactam ring-opening for the selective copper chelation and iii) the metal-mediated hydrolysis of the rhodamine moiety for fluorescence enhancement. In aqueous environment the molecule acts as a fluorescent reversible pH sensor and as colorimetric probe for Cu2+ at physiological pH; the hydrolysis of the copper targeting unit resulted in a 50-fold increase of the fluorescence intensity. Most importantly, in vitro cell analyses in undifferentiated (SH SY5Y) and differentiated (d-SH SY5Y) neuroblastoma cells, LysoBC1 is able to selectively accumulate into lysosome while the copper binding ability allowed us to monitor intracellular copper accumulation into lysosome.

The SH-SY5Y cell line: a valuable tool for Parkinson's disease drug discovery

INTRODUCTION

Owing to limited efficient treatment strategies for highly prevalent and distressing Parkinson's disease (PD), an impending need emerged for deciphering new modes and mechanisms for effective management. SH-SY5Y-based in vitro neuronal models have emerged as a new possibility for the elucidation of cellular and molecular processes in the pathogenesis of PD. SH-SY5Y cells are of human origin, adhered to catecholaminergic neuronal attributes, which consequences in imparting wide acceptance and significance to this model over conventional in vitro PD models for high-throughput screening of therapeutics.

AREAS COVERED

Herein, the authors review the SH-SY5Y cell line and its value to PD research. The authors also provide the reader with their expert perspectives on how these developments can lead to the development of new impactful therapeutics.

EXPERT OPINION

Encouraged by recent research on SH-SY5Y cell lines, it was envisaged that this in vitro model can serve as a primary model for assessing efficacy and toxicity of new therapeutics as well as for nanocarriers' capacity in delivering therapeutic agents across BBB. Considering the proximity with human neuronal environment as in pathogenic PD conditions, SH-SY5Y cell lines vindicated consistency and reproducibility in experimental results. Accordingly, exploitation of this standardized SH-SY5Y cell line can fast-track the drug discovery and development path for novel therapeutics.

Carnosic Acid Shows Higher Neuroprotective Efficiency than Edaravone or Ebselen in In Vitro Models of Neuronal Cell Damage

This study compared the neuroprotective efficacy of three antioxidants-the plant-derived carnosic acid (CA), and two synthetic free radical scavengers: edaravone (ED) and ebselen (EB)-in in vitro models of neuronal cell damage. Results showed that CA protected mouse primary neuronal cell cultures against hydrogen peroxide-induced damage more efficiently than ED or EB. The neuroprotective effects of CA were associated with attenuation of reactive oxygen species level and increased mitochondrial membrane potential but not with a reduction in caspase-3 activity. None of the tested substances was protective against glutamate or oxygen-glucose deprivation-evoked neuronal cell damage, and EB even increased the detrimental effects of these insults. Further experiments using the human neuroblastoma SH-SY5Y cells showed that CA but not ED or EB attenuated the cell damage induced by hydrogen peroxide and that the composition of culture medium is the critical factor in evaluating neuroprotective effects in this model. Our data indicate that the neuroprotective potential of CA, ED, and EB may be revealed in vitro only under specific conditions, with their rather narrow micromolar concentrations, relevant cellular model, type of toxic agent, and exposure time. Nevertheless, of the three compounds tested, CA displayed the most consistent neuroprotective effects.

Genotoxicity and cytotoxicity potential of organoselenium compounds in human leukocytes in vitro

In the current work, cytotoxicity and genotoxicity of different organoselenium compounds were examined using Trypan blue exclusion and alkaline comet assays with silver staining respectively. Leukocytes were subjected to a 3-hour incubation with organoselenium compounds at concentrations of 1, 5, 10, 25, 50, and 75 μM, or with the control vehicle (DMSO), at a temperature of 37 °C. The viability of the cells was evaluated using the Trypan blue exclusion method, while DNA damage was analyzed through the alkaline comet assay with silver staining. The exposure of leukocytes to different organoselenium compounds including i.e. (Z)-N-(pyridin-2-ylmethylene)-1-(2-((2-(1-((E)-pyridin-2-ylmethyleneamino)ethyl)phenyl)diselanyl)phenyl)ethanamine (C1), 2,2'(1Z,1'E)-(1,1'-(2,2'-diselanediylbis(2,1-phenylene))bis(ethane-1,1-diyl)) bis(azan-1-yl-1-ylidene)bis -methan-1-yl-1-ylidene)diphenol (C2), and dinaphthyl diselenide (NapSe)2, At concentrations ranging from 1 to 5 μM, no significant DNA damage was observed, as indicated by the absence of a noteworthy increase in the Damage Index (DI). Our results suggest that the organoselenium selenium compounds tested were not genotoxic and cytotoxic to human leukocytes in vitro at lower concentration. This study offers further insights into the genotoxicity profile of these organochalcogens in human leukocytes. Their genotoxicity and cytotoxicity effects at higher concentration are probably mediated through reactive oxygen species generation and their ability to catalyze thiol oxidation.

Enhancement of debitterness, water-solubility, and neuroprotective effects of naringin by transglucosylation

Naringin found in citrus fruits is a flavanone glycoside with numerous biological activities. However, the bitterness, low water-solubility, and low bioavailability of naringin are the main issues limiting its use in the pharmaceutical and nutraceutical industries. Herein, a glucansucrase from isolated Leuconostoc citreum NY87 was used for trans-α-glucosylattion of naringin by using sucrose as substrate. Two naringin glucosides (O-α-D-glucosyl-(1'''' → 6″) naringin (compound 1) and 4'-O-α-D-glucosyl naringin (compound 2)) were purified and determined their structures by nuclear magnetic resonance. The optimization condition for the synthesis of compound 1 was obtained at 10 mM naringin, 200 mM sucrose, and 337.5 mU/mL at 28 °C for 24 h by response surface methodology method. Compound 1 and compound 2 showed 1896- and 3272 times higher water solubility than naringin. Furthermore, the bitterness via the human bitter taste receptor TAS2R39 displayed that compound 1 was reduced 2.9 times bitterness compared with naringin, while compound 2 did not express bitterness at 1 mM. Both compounds expressed higher neuroprotective effects than naringin on human neuroblastoma SH-SY5Y cells treated with 5 mM scopolamine based on cell viability and cortisol content. Compound 1 reduced acetylcholinesterase activity more than naringin and compound 2. These results indicate that naringin glucosides could be utilized as functional material in the nutraceutical and pharmaceutical industries. KEY POINTS: • A novel O-α-D-glucosyl-(1 → 6) naringin was synthesized using glucansucrase from L. citreum NY87. • Naringin glucosides improved water-solubility and neuroprotective effects on SH-SY5Y cells. • Naringin glucosides showed a decrease in bitterness on bitter taste receptor 39.

A Multifunctional Conjugated Polymer Developed as an Efficient System for Differentiation of SH-SY5Y Tumour Cells

Polymer-based systems have been demonstrated in novel therapeutic and diagnostic (theranostic) treatments for cancer and other diseases. Polymers provide a useful scaffold to develop multifunctional nanosystems that combine various beneficial properties such as drug delivery, bioavailability, and photosensitivity. For example, to provide passive tumour targeting of small drug molecules, polymers have been used to modify and functionalise the surface of water-insoluble drugs. This approach also allows the reduction of adverse side effects, such as retinoids. However, multifunctional polymer conjugates containing several moieties with distinct features have not been investigated in depth. This report describes the development of a one-pot approach to produce a novel multifunctional polymer conjugate. As a proof of concept, we synthesised polyvinyl alcohol (PVA) covalently conjugated with rhodamine B (a tracking agent), folic acid (a targeting agent), and all-trans retinoic acid (ATRA, a drug). The obtained polymer (PVA@RhodFR) was characterised by MALDI-TOF mass spectrometry, gel permeation chromatography, thermal analysis, dynamic light-scattering, NMR, UV-Vis, and fluorescence spectroscopy. Finally, to evaluate the efficiency of the multifunctional polymer conjugate, cellular differentiation treatments were performed on the neuroblastoma SH-SY5Y cell line. In comparison with standard ATRA-based conditions used to promote cell differentiation, the results revealed the high capability of the new PVA@RhodFR to induce neuroblastoma cells differentiation, even with a short incubation time and low ATRA concentration.

Pre-differentiation exposure of PFOA induced persistent changes in DNA methylation and mitochondrial morphology in human dopaminergic-like neurons

Perfluorooctanoic acid (PFOA) is abundant in environment due to its historical uses in consumer products and industrial applications. Exposure to low doses of PFOA has been associated with various disease risks, including neurological disorders. The underlying mechanism, however, remains poorly understood. In this study, we examined the effects of low dose PFOA exposure at 0.4 and 4 μg/L on the morphology, epigenome, mitochondrion, and neuronal markers of dopaminergic (DA)-like SH-SY5Y cells. We observed persistent decreases in H3K4me3, H3K27me3 and 5 mC markers in nucleus along with alterations in nuclear size and chromatin compaction percentage in DA-like neurons differentiated from SH-SY5Y cells exposed to 0.4 and 4 μg/L PFOA. Among the selected epigenetic features, DNA methylation pattern can be used to distinguish between PFOA-exposed and naïve populations, suggesting the involvement of epigenetic regulation. Moreover, DA-like neurons with pre-differentiation PFOA exposure exhibit altered network connectivity, mitochondrial volume, and TH expression, implying impairment in DA neuron functionality. Collectively, our results revealed the prolonged effects of developmental PFOA exposure on the fitness of DA-like neurons and identified epigenome and mitochondrion as potential targets for bearing long-lasting changes contributing to increased risks of neurological diseases later in life.

Assessment of caffeine neurotoxicity using novel biomarkers of neural function in SH-SY5Y cells - Is there a need for environmental concern?

Worldwide usage of caffeine results in its constant release into the aquatic environment and growing concerns related to associated risks. We assessed (neuro)toxicity of environmentally relevant concentrations of caffeine, using novel biomarkers of neural function in SH-SY5Y cells and markers of general toxicity also in HepG2 cells. The RQ-PCR analyses showed that caffeine disturbs the expression of genes encoding several key elements of neurotransmitter pathways, with the most prominent responses observed for serotonin receptor 3A, dopamine receptor D2, monoamine oxidase B and GABA-transaminase. Expression of genes encoding synaptotagmin 10 involved in exocytosis of neurotransmitters and ATPase Na⁺/K⁺ transporting subunit alpha 3 was also disturbed. Caffeine stimulated the activity of monoamine oxidase, while cytotoxicity and effects on mitochondrial membrane potential were not observed. Our study points out the new possible molecular targets of caffeine and suggests that the raising concerns related to its growing environmental presence are justified.

Comparing the Neuroprotective Effects of Telmisartan, Perindopril, and Nebivolol Against Lipopolysaccharide-Induced Injury in Neuron-Like Cells

The effect of antihypertensive drugs, especially drugs modulating the renin-angiotensin-aldosterone-system (RAAS), on neurodegenerative diseases still needs to be investigated. This study aimed to compare the effects of three different antihypertensive drugs (telmisartan, perindopril, and nebivolol) on neuroprotection and acetylcholine (ACh) levels against lipopolysaccharide (LPS)-induced injury in a differentiated SH-SY5Y cell line. Cells were treated with retinoic acid for differentiation to a neuronal phenotype. LPS 20 (μg/mL) was applied to the cells for one hour. Then, the cells were treated with 1, 5, and 10 µg/mL concentrations of telmisartan, perindopril, and nebivolol separately for 24 hours, except for the control and LPS alone groups. Cell viability was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. ACh levels were analyzed using an enzyme immunosorbent assay in the culture medium. Tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) expressions were evaluated using western blot analysis. Telmisartan demonstrated the highest cell viability against LPS-induced injury, whereas the protective effect of perindopril was moderate. Nebivolol showed no neuroprotective effect. The protective effect of 10-µg/mL telmisartan was superior to 10 µg/mL perindopril (p=0.006), 5 µg/mL perindopril (p=0.001), 1 µg/mL perindopril (p=0.001), and 1, 5, and 10 µg/mL nebivolol (p<0.001). Among all the study drugs, only telmisartan provided a statistically significant increase in ACh levels after LPS-induced injury. Additionally, the administration of telmisartan provided a concentration-dependent reduction in TNF-α, IL-1β, and NFκB expression against LPS-induced neuroinflammation. These findings suggest that telmisartan has a superior neuroprotective effect against LPS-induced injury in neuron-like cells compared with both perindopril and nebivolol.

Phenylbenzothiazole derivatives: effects against a Trypanosoma cruzi infection and toxicological profiles

Current treatments for Chagas disease have a limited impact during the chronic stage and trigger severe side effects. Treatments target Trypanosoma cruzi, the etiological agent of the disease. The aims of this study were to evaluate the trypanocidal activity of four 2-phenylbenzothiazole derivatives (BZT1-4) in vitro by using the infectious and non-infectious forms of T. cruzi (trypomastigotes and epimastigotes, respectively) and to test the most promising compound (BZT4) in vivo in mice. Additionally, the toxicological profile and possible neuronal damage were examined. In relation to trypomastigotes, BZT4 was more selective and effective than the reference drug (benznidazole) during this infective stage, apparently due to the synergistic action of the CF₃ and COOH substituents in the molecule. During the first few hours post-administration of BZT4, parasitemia decreased by 40% in an in vivo model of short-term treatment, but parasite levels later returned to the basal state. In the long-term assessment, the compound did not produce a significant antiparasitic effect, only attaining a 30% reduction in parasitemia by day 20 with the dose of 16 mg/kg. The toxicity test was based on repeated dosing of BZT4 (administered orally) during 21 days, which did not cause liver damage. However, the compound altered the concentration of proteins and the proteinic profile of neuronal cells in vitro, perhaps leading to an effect on the central nervous system. Further research on the low trypanocidal activity in vivo compared to the better in vitro effect could possibly facilitate molecular redesign to improve trypanocidal activity.

Pyrimido[1,2-b]indazole derivatives: Selective inhibitors of human monoamine oxidase B with neuroprotective activity

Structurally diverse heterotricyclic compounds are recognized as monoamine oxidase (MAO) inhibitors and thus represent an appealing scaffold in development and optimization of novel MAO inhibitors. Herein we explored the chemical space of pyrimido[1,2-b]indazoles as MAO inhibitors by preparing a small library of (hetero)aryl derivatives. An efficient synthetic strategy was developed starting from commercially available 1H-indazol-3-amines, which were converted to various 3-bromoheterotricyclic derivatives and further functionalized via Suzuki-Miyaura coupling reaction. Derivatives 4a-t selectively inhibited human MAO-B isoform in a reversible and competitive manner as confirmed by kinetic experiments and docking studies. Selected derivatives were not cytotoxic to neuroblastoma SH-SY5Y cells. Moreover, analogue 4i protected human neuroblastoma SH-SY5Y cells against 6-hydroxydopamine-induced cell death, which confirms the applicability of the pyrimido[1,2-b]indazoles as potential antiparkinsonian agents.

In utero treatment of myelomeningocele with placental mesenchymal stromal cells - Selection of an optimal cell line in preparation for clinical trials

BACKGROUND

We determined whether in vitro potency assays inform which placental mesenchymal stromal cell (PMSC) lines produce high rates of ambulation following in utero treatment of myelomeningocele in an ovine model.

METHODS

PMSC lines were created following explant culture of three early-gestation human placentas. In vitro neuroprotection was assessed with a neuronal apoptosis model. In vivo, myelomeningocele defects were created in 28 fetuses and repaired with PMSCs at 3 × 105 cells/cm2 of scaffold from Line A (n = 6), Line B (n = 7) and Line C (n = 5) and compared to no PMSCs (n = 10). Ambulation was scored as ≥13 on the Sheep Locomotor Rating Scale.

RESULTS

In vitro, Line A and B had higher neuroprotective capability than no PMSCs (1.7 and 1.8 respectively vs 1, p = 0.02, ANOVA). In vivo, Line A and B had higher large neuron densities than no PMSCs (25.2 and 27.9 respectively vs 4.8, p = 0.03, ANOVA). Line C did not have higher neuroprotection or larger neuron density than no PMSCs. In vivo, Line A and B had ambulation rates of 83% and 71%, respectively, compared to 60% with Line C and 20% with no PMSCs.

CONCLUSION

The in vitro neuroprotection assay will facilitate selection of optimal PMSC lines for clinical use.

LEVEL OF EVIDENCE

n/a.

TYPE OF STUDY

Basic science.

Plasma Homocysteine Concentration is Associated with the Expression Level of Folate Receptor 3

Folic acid and folate receptors (FOLRs) play an important role in the downregulation of homocysteine (Hcy), a risk factor of Alzheimer's disease, thrombosis, neuropsychiatric illness and fractures. While several studies have reported that FOLR1 and FOLR2 import folic acid into cells, the role of FOLR3 remains unknown. In this study, we evaluated the impact of FOLR3 on the metabolism of Hcy alongside its protective effect against homocysteine-induced neurotoxicity. To reveal the role of FOLR3, we constructed FOLR3-overexpressed HEK293 cells (FOLR3+ cells) and evaluated cell growth, folic acid intake and Hcy-induced neurotoxicity. Subjects with a high expression of FOLR3 exhibited low levels of plasma homocysteine. The ectopic expression of FOLR3 enhanced cell growth, and the enhanced effect was neutralised by folic acid-deficient media. The Western blot analysis revealed that FOLR3 is secreted into cell supernatant. The folic acid intake of FOLR3+ cells was higher than that of wild-type cells. Supernatant from FOLR3+ cells showed a protective effect on Hcy-induced cytotoxicity. FOLR3 expression in plasma is negatively correlated with plasma homocysteine. Our study emphasizes the role of FOLR3 in the intake of folic acid into cells on the one hand and its protective role in Hcy-induced cytotoxicity on the other.

Design of novel monoamine oxidase-B inhibitors based on piperine scaffold: Structure-activity-toxicity, drug-likeness and efflux transport studies

Piperine has been associated with neuroprotective effects and monoamine oxidase (MAO) inhibition, thus being an attractive scaffold to develop new antiparkinsonian agents. Accordingly, we prepared a small library of piperine derivatives and screened the inhibitory activities towards human MAO isoforms (hMAO-A and hMAO-B). Structure-activity relationship (SAR) studies pointed out that the combination of α-cyano and benzyl ester groups increased both potency and selectivity towards hMAO-B. Kinetic experiments with compounds 7, 10 and 15 indicated a competitive hMAO-B inhibition mechanism. Compounds 15 and 16, at 10 μM, caused a small but significant decrease in P-gp efflux activity in Caco-2 cells. Compound 15 stands out as the most potent piperine-based hMAO-B inhibitor (IC₅₀ = 47.4 nM), displaying favourable drug-like properties and a broad safety window. Compound 15 is thus a suitable candidate for lead optimization and the development of multitarget-directed ligands.

Neuroprotective effect of placenta-derived mesenchymal stromal cells: role of exosomes

We have established early-gestation chorionic villus-derived placenta mesenchymal stromal cells (PMSCs) as a potential treatment for spina bifida (SB), a neural tube defect. Our preclinical studies demonstrated that PMSCs have the potential to cure hind limb paralysis in the fetal lamb model of SB via a paracrine mechanism. PMSCs exhibit neuroprotective function by increasing cell number and neurites, as shown by indirect coculture and direct addition of PMSC-conditioned medium to the staurosporine-induced apoptotic human neuroblastoma cell line, SH-SY5Y. PMSC-conditioned medium suppressed caspase activity in apoptotic SH-SY5Y cells, suggesting that PMSC secretome contributes to neuronal survival after injury. As a part of PMSC secretome, PMSC exosomes were isolated and extensively characterized; their addition to apoptotic SH-SY5Y cells mediated an increase in neurites, suggesting that they exhibit neuroprotective function. Proteomic and RNA sequencing analysis revealed that PMSC exosomes contain several proteins and RNAs involved in neuronal survival and development. Galectin 1 was highly expressed on the surface of PMSCs and PMSC exosomes. Preincubation of exosomes with anti-galectin 1 antibody decreased their neuroprotective effect, suggesting that PMSC exosomes likely impart their effect via binding of galectin 1 to cells. Future studies will include in-depth analyses of the role of PMSC exosomes on neuroprotection and their clinical applications.-Kumar, P., Becker, J. C., Gao, K., Carney, R. P., Lankford, L., Keller, B. A., Herout, K., Lam, K. S., Farmer, D. L., Wang, A. Neuroprotective effect of placenta-derived mesenchymal stromal cells: role of exosomes.

Cholinergic Differentiation of Human Neuroblastoma SH-SY5Y Cell Line and Its Potential Use as an In vitro Model for Alzheimer's Disease Studies

Cholinergic transmission is critical to high-order brain functions such as memory, learning, and attention. Alzheimer's disease (AD) is characterized by cognitive decline associated with a specific degeneration of cholinergic neurons. No effective treatment to prevent or reverse the symptoms is known. Part of this might be due to the lack of in vitro models that effectively mimic the relevant features of AD. Here, we describe the characterization of an AD in vitro model using the SH-SY5Y cell line. Exponentially growing cells were maintained in DMEM/F12 medium and differentiation was triggered by the combination of retinoic acid (RA) and BDNF. Both acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) enzymatic activities and immunocontent were determined. For mimicking tau and amyloid-β pathology, RA + BDNF-differentiated cells were challenged with okadaic acid (OA) or soluble oligomers of amyloid-β (AβOs) and neurotoxicity was evaluated. RA + BDNF-induced differentiation resulted in remarkable neuronal morphology alterations characterized by increased neurite density. Enhanced expression and enzymatic activities of cholinergic markers were observed compared to RA-differentiation only. Combination of sublethal doses of AβOs and OA resulted in decreased neurite densities, an in vitro marker of synaptopathy. Challenging RA + BDNF-differentiated SH-SY5Y cells with the combination of sublethal doses of OA and AβO, without causing considerable decrease of cell viability, provides an in vitro model which mimics the early-stage pathophysiology of cholinergic neurons affected by AD.

Acute oral toxicity and antioxidant studies of an amine-based diselenide

Background

Organochalcogen compounds have attracted the interest of a multitude of studies for their promising Pharmacological and biological activities. The antioxidant activity and acute toxicity of an organoselenium compound, 1-(2-(2-(2-(1-aminoethyl)phenyl)diselanyl)phenyl)ethanamine (APDP) was determined in mice.

Methods

Mice were randomly divided into four groups, with each group comprising of seven animals. Canola oil (1ml/kg of body weight) was administered to 1st group, while 2nd, 3rd & 4th groups were administered with 10 mg/kg, 30 mg/kg & 350 mg/kg of APDP respectively. APDP was administered by Intragastric gavage as a single oral dose.

Results

The APDP oral administration was found to be safe up to 350 mg/kg of body weight and no deaths of animals were recorded. The lethal dose 50 (LD₅₀) for APDP was determined at 72 h and was estimated to be > 350 mg/kg. After acute treatment, all mice were sacrificed by decapitation to determine the antioxidant enzymes and lipid peroxidation values for the treated mice liver. No fluctuation in lipid peroxidation, vitamin C and non protein thiol (NPSH) levels was observed due to the administration of APDP. hepatic α-ALA-D activity, catalase (CAT), superoxide dismutase (SOD) and the biochemical parameters were evaluated. Experimental observation demonstrated that APDP protected Fe(II) induced thiobarbituric acid reactive substances (TBARS) production in liver homogenate significantly (p < 0.05). The administration of APDP (an amine-based diselenide) both in vitro and in vivo clearly demonstrated that this potential compound has no acute toxicity towards mice among all the tested parameter.

Conclusion

On the basis of experimental results, it is concluded that APDP is a potential candidate as an antioxidant compound for studying pharmacological properties.

Chemical Composition and In Vitro Neuroprotective Activity of Fibre-Type Cannabis sativa L. (Hemp)

Background:

Fibre-type Cannabis sativa L. (hemp) usually contains cannabidiolic acid and cannabidiol as the main non-psychoactive cannabinoids. Even though there is evidence of the neuroprotective activity of pure cannabidiol, no in vitro studies have reported so far the role of hemp extracts on neuroprotection. The objective of this study was to evaluate the neuroprotective effect of hemp extracts in in vitro cellular models of neurotoxicity.

Methods:

One extract was obtained from raw hemp inflorescences, while the other was prepared from the same plant material submitted to a decarboxylation process. The composition of both these extracts was evaluated by HPLC-UV/DAD. Human neuroblastoma SH-SY5Y and microglial BV-2 cell lines treated with rotenone were selected as the model of neurodegeneration. The neuroprotection of hemp extracts was assessed also in serum-free conditions both in the presence and in the absence of rotenone as the toxic agent by using the same cell lines. The neuroprotective potential of cannabidiol was tested in parallel.

Results:

The decarboxylated hemp extract possesses a mild neuroprotective activity on BV-2 cells treated with rotenone, higher than that of pure cannabidiol. As regards serum-free experiments, the nondecarboxylated hemp extract was the most effective neuroprotective agent toward SH-SY5Y cells, while BV-2 cells were better protected from the toxic insult by the decarboxylated extract and cannabidiol.

Conclusion:

Both hemp extracts and pure cannabidiol displayed a moderate neuroprotective activity in the neurotoxicity models considered in this study; in addition, they showed a trophic effect on SHSY5Y cells.

Insights into the differential toxicological and antioxidant effects of 4-phenylchalcogenil-7-chloroquinolines in Caenorhabditis elegans

Organic selenium and tellurium compounds are known for their broad-spectrum effects in a variety of experimental disease models. However, these compounds commonly display high toxicity and the molecular mechanisms underlying these deleterious effects have yet to be elucidated. Thus, the need for an animal model that is inexpensive, amenable to high-throughput analyses, and feasible for molecular studies is highly desirable to improve organochalcogen pharmacological and toxicological characterization. Herein, we use Caenorhabdtis elegans (C. elegans) as a model for the assessment of pharmacological and toxicological parameters following exposure to two 4-phenylchalcogenil-7-chloroquinolines derivatives (PSQ for selenium and PTQ for tellurium-containing compounds). While non-lethal concentrations (NLC) of PTQ and PSQ attenuated paraquat-induced effects on survival, lifespan and oxidative stress parameters, lethal concentrations (LC) of PTQ and PSQ alone are able to impair these parameters in C. elegans. We also demonstrate that DAF-16/FOXO and SKN-1/Nrf2 transcription factors underlie the mechanism of action of these compounds, as their targets sod-3, gst-4 and gcs-1 were modulated following exposures in a daf-16- and skn-1-dependent manner. Finally, in accordance with a disturbed thiol metabolism in both LC and NLC, we found higher sensitivity of trxr-1 worm mutants (lacking the selenoprotein thioredoxin reductase 1) when exposed to PSQ. Finally, our study suggests new targets for the investigation of organochalcogen pharmacological effects, reinforcing the use of C. elegans as a powerful platform for preclinical approaches.

Transcriptomic Profiling Discloses Molecular and Cellular Events Related to Neuronal Differentiation in SH-SY5Y Neuroblastoma Cells

Human SH-SY5Y neuroblastoma cells are widely utilized in in vitro studies to dissect out pathogenetic mechanisms of neurodegenerative disorders. These cells are considered as neuronal precursors and differentiate into more mature neuronal phenotypes under selected growth conditions. In this study, in order to decipher the pathways and cellular processes underlying neuroblastoma cell differentiation in vitro, we performed systematic transcriptomic (RNA-seq) and bioinformatic analysis of SH-SY5Y cells differentiated according to a two-step paradigm: retinoic acid treatment followed by enriched neurobasal medium. Categorization of 1989 differentially expressed genes (DEGs) identified in differentiated cells functionally linked them to changes in cell morphology including remodelling of plasma membrane and cytoskeleton, and neuritogenesis. Seventy-three DEGs were assigned to axonal guidance signalling pathway, and the expression of selected gene products such as neurotrophin receptors, the functionally related SLITRK6, and semaphorins, was validated by immunoblotting. Along with these findings, the differentiated cells exhibited an ability to elongate longer axonal process as assessed by the neuronal cytoskeletal markers biochemical characterization and morphometric evaluation. Recognition of molecular events occurring in differentiated SH-SY5Y cells is critical to accurately interpret the cellular responses to specific stimuli in studies on disease pathogenesis.

The Chemical Molecule B355252 is Neuroprotective in an In Vitro Model of Parkinson's Disease

6-Hydroxydopamine (6-OHDA) is a neurotoxin frequently used to create in vitro and in vivo experimental models of Parkinson's disease (PD), a chronic neurodegenerative disorder largely resulting from damage to the nigrostriatal dopaminergic pathway. No effective drugs or therapies have been developed for this devastating disorder, and current regimens of symptomatic therapeutics only alleviate symptoms temporarily. Therefore, effective treatments that reverse or cure this disorder are urgently needed. The aim of the study described in this report was to investigate the therapeutic impact of B355252, an aryl thiophene sulfonamide chemical entity, in the widely recognized in vitro model of PD, and to characterize the molecular signaling pathways. We show here that 6-OHDA-induced cell death in HT22, a murine neuronal cell model, through a pathway that involves the mitochondria by increasing the levels of reactive oxygen species (ROS), raising intracellular calcium ([Ca(2+)]i), enhancing the release of cytochrome c to the cytosol, and promoting activation of stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) signaling pathway. More importantly, we found that B355252 protected HT22 neurons against 6-OHDA toxin-induced neuronal cell death by significant attenuation of ROS production, blocking of mitochondrial depolarization, inhibition of cytochrome c release, sequestration of [Ca(2+)]i, modulation of JNK cascade, and strong inhibition of caspase 3/7 cleavage. Overall, this study demonstrates that death of neurons under toxic conditions characteristic of PD can be efficiently halted by B355252 and suggests that further development of the molecule could be potentially beneficial as a therapeutic prevention or treatment option for PD.

Impact of Plant-Derived Flavonoids on Neurodegenerative Diseases

Neurodegenerative disorders have a common characteristic that is the involvement of different cell types, typically the reactivity of astrocytes and microglia, characterizing gliosis, which in turn contributes to the neuronal dysfunction and or death. Flavonoids are secondary metabolites of plant origin widely investigated at present and represent one of the most important and diversified among natural products phenolic groups. Several biological activities are attributed to this class of polyphenols, such as antitumor activity, antioxidant, antiviral, and anti-inflammatory, among others, which give significant pharmacological importance. Our group have observed that flavonoids derived from Brazilian plants Dimorphandra mollis Bent., Croton betulaster Müll. Arg., e Poincianella pyramidalis Tul., botanical synonymous Caesalpinia pyramidalis Tul. also elicit a broad spectrum of responses in astrocytes and neurons in culture as activation of astrocytes and microglia, astrocyte associated protection of neuronal progenitor cells, neuronal differentiation and neuritogenesis. It was observed the flavonoids also induced neuronal differentiation of mouse embryonic stem cells and human pluripotent stem cells. Moreover, with the objective of seeking preclinical pharmacological evidence of these molecules, in order to assess its future use in the treatment of neurodegenerative disorders, we have evaluated the effects of flavonoids in preclinical in vitro models of neuroinflammation associated with Parkinson's disease and glutamate toxicity associated with ischemia. In particular, our efforts have been directed to identify mechanisms involved in the changes in viability, morphology, and glial cell function induced by flavonoids in cultures of glial cells and neuronal cells alone or in interactions and clarify the relation with their neuroprotective and morphogetic effects.

Stimulus-dependent neuronal cell responses in SH-SY5Y neuroblastoma cells

The aim of the present study was to elucidate the intracellular mechanisms that cause neuronal cell death following exposure to excitatory neurotransmitter‑induced neurotoxicity, neurotoxins and oxidative stress. Human SH‑SY5Y neuroblastoma cells were exposed to various stimuli, including glutamate, 6‑hydroxydopamine (6‑OHDA), and glucose oxidase, and cell viability was determined by MTT assay. Early apoptosis and necrosis were examined by Annexin V/propidium iodide double staining and flow cytometric analysis. Intracellular calcium ion concentration and mitochondrial membrane potential were assessed by Fluo‑3a and JC‑1 staining, respectively. In addition, protein expression of receptor‑interacting protein (RIP) kinase 1 and RIP kinase 3 were evaluated by western blotting. Glutamate, 6‑OHDA and glucose oxidase treatment decreased cell viability. Glutamate induced apoptosis and necrosis, whereas, 6‑OHDA induced cell necrosis and glucose oxidase induced apoptosis. Furthermore, glutamate, 6‑OHDA or glucose oxidase treatment significantly increased intracellular calcium concentrations (P<0.05). The effect of glutamate on mitochondrial membrane potential varied with high and low concentrations, whereas 6‑OHDA and glucose oxidase significantly increased the mitochondrial membrane potential in the SH‑SY5Y cells (P<0.05). Glutamate significantly upregulated expression levels of RIP kinase 1 (P<0.05), but not RIP kinase 3. These findings demonstrate that the response of SH‑SY5Y cells varies with the stimuli. Furthermore, RIP kinase 1 may specifically regulate programmed necrosis in glutamate‑mediated excitatory toxicity, but not in cell damage induced by either 6-OHDA or glucose oxidase.

Characterization of Differentiated SH-SY5Y as Neuronal Screening Model Reveals Increased Oxidative Vulnerability

The immortalized and proliferative cell line SH-SY5Y is one of the most commonly used cell lines in neuroscience and neuroblastoma research. However, undifferentiated SH-SY5Y cells share few properties with mature neurons. In this study, we present an optimized neuronal differentiation protocol for SH-SY5Y that requires only two work steps and 6 days. After differentiation, the cells present increased levels of ATP and plasma membrane activity but reduced expression of energetic stress response genes. Differentiation results in reduced mitochondrial membrane potential and decreased robustness toward perturbations with 6-hydroxydopamine. We are convinced that the presented differentiation method will leverage genetic and chemical high-throughput screening projects targeting pathways that are involved in the selective vulnerability of neurons with high energetic stress levels.

Neurotoxin mechanisms and processes relevant to Parkinson's disease: an update

The molecular mechanism responsible for degenerative process in the nigrostriatal dopaminergic system in Parkinson's disease (PD) remains unknown. One major advance in this field has been the discovery of several genes associated to familial PD, including alpha synuclein, parkin, LRRK2, etc., thereby providing important insight toward basic research approaches. There is an consensus in neurodegenerative research that mitochon dria dysfunction, protein degradation dysfunction, aggregation of alpha synuclein to neurotoxic oligomers, oxidative and endoplasmic reticulum stress, and neuroinflammation are involved in degeneration of the neuromelanin-containing dopaminergic neurons that are lost in the disease. An update of the mechanisms relating to neurotoxins that are used to produce preclinical models of Parkinson´s disease is presented. 6-Hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and rotenone have been the most wisely used neurotoxins to delve into mechanisms involved in the loss of dopaminergic neurons containing neuromelanin. Neurotoxins generated from dopamine oxidation during neuromelanin formation are likewise reviewed, as this pathway replicates neurotoxin-induced cellular oxidative stress, inactivation of key proteins related to mitochondria and protein degradation dysfunction, and formation of neurotoxic aggregates of alpha synuclein. This survey of neurotoxin modeling-highlighting newer technologies and implicating a variety of processes and pathways related to mechanisms attending PD-is focused on research studies from 2012 to 2014.

In vitro models for neurotoxicology research

The nervous system has a highly complex organization, including many cell types with multiple functions, with an intricate anatomy and unique structural and functional characteristics; the study of its (dys)functionality following exposure to xenobiotics, neurotoxicology, constitutes an important issue in neurosciences.

Ginsenoside Re protects methamphetamine-induced mitochondrial burdens and proapoptosis via genetic inhibition of protein kinase C δ in human neuroblastoma dopaminergic SH-SY5Y cell lines

Recently, we have demonstrated that ginsenoside Re protects methamphetamine (MA)-induced dopaminergic toxicity in mice via genetic inhibition of PKCδ and attenuation of mitochondrial stress. In addition, we have reported that induction of mitochondrial glutathione peroxidase (GPx) is also important for neuroprotection mediated by ginsenoside Re. To extend our knowledge, we examined the effects of ginsenoside Re against MA toxicity in vitro condition using SH-SY5Y neuroblastoma cells. Treatment with ginsenoside Re resulted in significant attenuations against a decrease in the activity of GPx and an increase in the activity of superoxide dismutase (SOD) in the cytosolic and mitochondrial fraction. The changes in glutathione (GSH) paralleled those in GPx in the same experimental condition. Consistently, ginsenoside Re treatment exhibited significant protections against cytosolic and mitochondrial oxidative damage (i.e. lipid peroxidation and protein oxidation), mitochondrial translocation of PKCδ, mitochondrial dysfunction (mitochondrial transmembrane potential and intra-mitochondrial Ca(2+)), apoptotic events [i.e., cytochrome c release from mitochondria, cleavage of caspase-3 and poly(ADP-ribose)polymerase-1, nuclear condensation, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic cells], and a reduction in the tyrosine hydroxylase (TH) expression and TH activity induced by MA in SH-SY5Y neuroblastoma cells. These protective effects of ginsenoside Re were comparable to those of PKCδ antisense oligonucleotide (ASO). However, ginsenoside Re did not significantly provide additional protective effects mediated by genetic inhibition of PKCδ. Our results suggest that PKCδ is a specific target for ginsenoside Re-mediated protective activity against MA toxicity in SH-SY5Y neuroblastoma cells.

Cannabidiol Exposure During Neuronal Differentiation Sensitizes Cells Against Redox-Active Neurotoxins

Cannabidiol (CBD), one of the most abundant Cannabis sativa-derived compounds, has been implicated with neuroprotective effect in several human pathologies. Until now, no undesired side effects have been associated with CBD. In this study, we evaluated CBD's neuroprotective effect in terminal differentiation (mature) and during neuronal differentiation (neuronal developmental toxicity model) of the human neuroblastoma SH-SY5Y cell line. A dose-response curve was performed to establish a sublethal dose of CBD with antioxidant activity (2.5 μM). In terminally differentiated SH-SY5Y cells, incubation with 2.5 μM CBD was unable to protect cells against the neurotoxic effect of glycolaldehyde, methylglyoxal, 6-hydroxydopamine, and hydrogen peroxide (H2O2). Moreover, no difference in antioxidant potential and neurite density was observed. When SH-SY5Y cells undergoing neuronal differentiation were exposed to CBD, no differences in antioxidant potential and neurite density were observed. However, CBD potentiated the neurotoxicity induced by all redox-active drugs tested. Our data indicate that 2.5 μM of CBD, the higher dose tolerated by differentiated SH-SY5Y neuronal cells, does not provide neuroprotection for terminally differentiated cells and shows, for the first time, that exposure of CBD during neuronal differentiation could sensitize immature cells to future challenges with neurotoxins.

A Potent (R)-alpha-bis-lipoyl Derivative Containing 8-Hydroxyquinoline Scaffold: Synthesis and Biological Evaluation of Its Neuroprotective Capabilities in SH-SY5Y Human Neuroblastoma Cells

A novel bis-lipoyl derivative containing 8-hydroxyquinoline scaffold (LA-HQ-LA, 5) was synthesized as a new multifunctional drug candidate with antioxidant, chelant, and neuroprotective properties for the treatment of neurodegenerative diseases. We have investigated the potential effectiveness of LA-HQ-LA against the cytotoxicity induced by 6-OHDA and H2O2 on human neuroblastoma SH-SY5Y cell line. Our outcomes showed that LA-HQ-LA resulted in significant neuroprotective and antioxidant effects against H2O2- and 6-OHDA-induced neurotoxicity in human neuroblastoma SH-SY5Y cells, as assessed by MTT assay. In particular, it showed potent neuroprotective effects against 6-OHDA in RA/PMA differentiated cells at all the tested concentrations.

(R)-α-lipoyl-glycyl-L-prolyl-L-glutamyl dimethyl ester codrug as a multifunctional agent with potential neuroprotective activities

The (R)-α-lipoyl-glycyl-L-prolyl-L-glutamyl dimethyl ester codrug (LA-GPE, 1) was synthesized as a new multifunctional drug candidate with antioxidant and neuroprotective properties for the treatment of neurodegenerative diseases. Physicochemical properties, chemical and enzymatic stabilities were evaluated, along with the capacity of LA-GPE to penetrate the blood-brain barrier (BBB) according to an in vitro parallel artificial membrane permeability assay for the BBB. We also investigated the potential effectiveness of LA-GPE against the cytotoxicity induced by 6-hydroxydopamine (6-OHDA) and H2O2 on the human neuroblastoma cell line SH-SY5Y by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Our results show that codrug 1 is stable at both pH 1.3 and 7.4, exhibits good lipophilicity (log P=1.51) and a pH-dependent permeability profile. Furthermore, LA-GPE was demonstrated to be significantly neuroprotective and to act as an antioxidant against H2O2- and 6-OHDA-induced neurotoxicity in SH-SY5Y cells.

Distinct effects of rotenone, 1-methyl-4-phenylpyridinium and 6-hydroxydopamine on cellular bioenergetics and cell death

Parkinson's disease is characterized by dopaminergic neurodegeneration and is associated with mitochondrial dysfunction. The bioenergetic susceptibility of dopaminergic neurons to toxins which induce Parkinson's like syndromes in animal models is then of particular interest. For example, rotenone, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active metabolite 1-methyl-4-phenylpyridinium (MPP(+)), and 6-hydroxydopamine (6-OHDA), have been shown to induce dopaminergic cell death in vivo and in vitro. Exposure of animals to these compounds induce a range of responses characteristics of Parkinson's disease, including dopaminergic cell death, and Reactive Oxygen Species (ROS) production. Here we test the hypothesis that cellular bioenergetic dysfunction caused by these compounds correlates with induction of cell death in differentiated dopaminergic neuroblastoma SH-SY5Y cells. At increasing doses, rotenone induced significant cell death accompanied with caspase 3 activation. At these concentrations, rotenone had an immediate inhibition of mitochondrial basal oxygen consumption rate (OCR) concomitant with a decrease of ATP-linked OCR and reserve capacity, as well as a stimulation of glycolysis. MPP(+) exhibited a different behavior with less pronounced cell death at doses that nearly eliminated basal and ATP-linked OCR. Interestingly, MPP(+), unlike rotenone, stimulated bioenergetic reserve capacity. The effects of 6-OHDA on bioenergetic function was markedly less than the effects of rotenone or MPP(+) at cytotoxic doses, suggesting a mechanism largely independent of bioenergetic dysfunction. These studies suggest that these dopaminergic neurotoxins induce cell death through distinct mechanisms and differential effects on cellular bioenergetics.

Recent advances on the neuroprotective potential of antioxidants in experimental models of Parkinson's disease

Parkinson’s disease (PD), a neurodegenerative movement disorder of the central nervous system (CNS) is characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta region of the midbrain. Although the etiology of PD is not completely understood and is believed to be multifactorial, oxidative stress and mitochondrial dysfunction are widely considered major consequences, which provide important clues to the disease mechanisms. Studies have explored the role of free radicals and oxidative stress that contributes to the cascade of events leading to dopamine cell degeneration in PD. In general, in-built protective mechanisms consisting of enzymatic and non-enzymatic antioxidants in the CNS play decisive roles in preventing neuronal cell loss due to free radicals. But the ability to produce these antioxidants decreases with aging. Therefore, antioxidant therapy alone or in combination with current treatment methods may represent an attractive strategy for treating or preventing the neurodegeneration seen in PD. Here we summarize the recent discoveries of potential antioxidant compounds for modulating free radical mediated oxidative stress leading to neurotoxicity in PD.