Morphological Differentiation Towards Neuronal Phenotype of SH-SY5Y Neuroblastoma Cells by Estradiol, Retinoic Acid and Cholesterol

Hericium erinaceus extracts promote neuronal differentiation and excitability through nootropic metabolite activity

This study investigates the effects of a blend of Hericium erinaceus (lion's mane mushroom) extract on the differentiation of SH-SY5Y cells, a human neuroblastoma cell line, revealing potential therapeutic implications for neuroblastoma management. Treatment with this blend induced cells differentiation towards a neuron-like profile, as evidenced by enhanced neuronal excitability and upregulation of neuronal markers, such as βIII-tubulin and synaptotagmin. Additionally, the treatment significantly reduced PCNA, a key regulator of proliferation, alongside a decrease in stemness markers, indicating a shift toward a more mature and less proliferative phenotype. These findings demonstrate the ability of Hericium erinaceus to promote neuronal differentiation and inhibit proliferation in neuroblastoma cells, highlighting its therapeutic potential for managing neuroblastoma and potentially other neurological disorders. The results suggest that Hericium erinaceus may serve as a promising candidate for the development of novel neuroregenerative therapies.

Exploring therapeutic potential of Bacopa monnieri bioactive compounds against Alzheimer's and Parkinson's diseases

Parkinson's disease (PD) and Alzheimer's disease (AD) consist of progressive illnesses of central nervous system that primarily affect the elderly and are characterized by movement symptoms, memory decline, and cognitive impairment. A number of variables, including the lack of a novel treatment, a steady rise in the patient population, and the high expense of care and treatment, have contributed to the growing significance of these diseases. In recent decades, we have gained a better understanding of the causes of diseases, but complex mechanisms of neuronal loss, combined with physiological factors that are incompatible, pose challenges in describing the pathogenic processes and devising effective treatments. Currently, there are no known treatments for most of these diseases, rendering them incurable. Therefore, there is a pressing need for therapeutic interventions that have the potential to effectively treat neurodegeneration. This study aimed to evaluate the efficacy of the ayurvedic herb Bacopa monnieri bioactive components against the therapeutic targets HTR1A, HTR1B, HTR2A, HTR2C, HTR7, alpha-synuclein, amyloid beta, and tau protein of Alzheimer's and Parkinson's illnesses. The docking analysis revealed the promising binding affinity with Quercetin, Apigenin, and Luteolin and Molecular mechanics/generalized Born surface area (MM/GBSA) further confirmed the stability of the complexes. In vitro investigation indicated that Quercetin is the most effective for treating AD and PD due to its considerable inhibition of alpha-synuclein production, whereas Luteolin is the favorable one for preventing both diseases by mitigating effects during Rotenone treatment. The future implications and constraints of the current study suggest that further validation in Invivo models of Alzheimer's and Parkinson's diseases is necessary to investigate the effects of Quercetin and Apigenin in the treatment of these conditions, as well as Luteolin and Quercetin for their prevention.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04224-6.

Retinoic Acid Promotes Neuronal Differentiation While Increasing Proteins and Organelles Related to Autophagy

Retinoic acid (RA) is commonly used to differentiate SH-SY5Y neuroblastoma cells. This effect is sustained by a specific modulation of gene transcription, leading to marked changes in cellular proteins. In this scenario, autophagy may be pivotal in balancing protein synthesis and degradation. The present study analyzes whether some autophagy-related proteins and organelles are modified during RA-induced differentiation of SH-SY5Y cells. RA-induced effects were compared to those induced by starvation. SH-SY5Y cells were treated with a single dose of 10 µM RA or grown in starvation, for 3 days or 7 days. After treatments, cells were analyzed at light microscopy and transmission electron microscopy to assess cell morphology and immunostaining for specific markers (nestin, βIII-tubulin, NeuN) and some autophagy-related proteins (Beclin 1, LC3). We found that both RA and starvation differentiate SH-SY5Y cells. Specifically, cell differentiation was concomitant with an increase in autophagy proteins and autophagy-related organelles. However, the effects of a single dose of 10 μM RA persist for at least 7 days, while prolonged starvation produces cell degeneration and cell loss. Remarkably, the effects of RA are modulated in the presence of autophagy inhibitors or stimulators. The present data indicate that RA-induced differentiation is concomitant with an increased autophagy.

Differentiated and mature neurons are more responsive to neurotoxicant exposure at both transcriptional and translational levels

SH-SY5Y human neuroblastoma cells have been extensively used as an in vitro model system in a diverse range of studies involving neurodevelopment, neurotoxicity, neurodegeneration, and neuronal ageing. Both naïve and differentiated phenotypes of SH-SY5Y cells are utilized to model human neurons under in vitro conditions. The process of differentiation causes extensive remodeling of neuronal cells at multiple omic levels, including the epigenome and proteome. In the present investigation, the miRNAome and proteome profiles of arsenic-treated naïve and differentiated SH-SY5Y cells were generated using the miRNA OpenArray technology and high-resolution mass spectrometry. Our findings demonstrated that differentiation dramatically affected the response of SH-SY5Y cells to toxicant exposure, as indicated by increased tolerance of differentiated cells against arsenic exposure compared to naïve cells in cell viability assay. Arsenic-exposed naïve and differentiated SH-SY5Y cells possess distinct miRNA and protein profiles with few similarities. Compared to naïve cells, differentiated cells have undergone higher deregulation in the expression of brain-enriched miRNAs and proteins and have shown a more drastic decrease in oxygen consumption rate, which is a measure of mitochondrial respiration after exposure to arsenic. Proteins identified in arsenic-treated differentiated SH-SY5Y cells were more enriched in pathways underlying multifactorial neurotoxic events. Additionally, more functional regulatory modules have been identified between the miRNAs and proteins differentially expressed in arsenic-treated differentiated SH-SY5Y cells relative to naïve cells. Collectively, our studies have shown that differentiated SH-SY5Y cells displayed alterations in the expression of a greater number of miRNAs and proteins following neurotoxicant exposure, indicating their higher responsivity.

Dopamine D1-Like Receptor Stimulation Induces CREB, Arc, and BDNF Dynamic Changes in Differentiated SH-SY5Y Cells

The dopamine D1-like receptor is a dopamine (DA) receptor regulating diverse brain functions. Once the dopamine D1-like receptor is activated, it induces activation of the Protein Kinase A (PKA) that phosphorylates the cAMP Response Element-Binding (CREB) transcription factor, which once active elicits the expression of the critical synaptic elements Activity-regulated cytoskeleton-associated (Arc) and the Brain-Derived Neurotrophic Factor (BDNF). The temporality and subcellular localization of proteins impact brain function. However, there is no information about the temporality of CREB activation and Arc and BDNF levels induced through dopamine D1-like receptor activation. In this study, we aimed to assess the specific effect of dopamine D1-like receptor activation on the temporality of CREB-phosphorylation (p-CREBS133) and the spatiotemporal induction of Arc and BDNF. Using SY-SY5Y cells differentiated with Retinoic Acid (RA), the dopamine D1-like receptor activation with a specific agonist transiently increased p-CREBS133 at 30 min of stimulation. It induced two spikes of Arc protein at 15 min and 6 h, forming clusters near the cell membrane. BDNF secretion temporarily increased, reaching a maximum at 6 h, while secretion was lower at 24 h compared to the unstimulated group. Our results provide new insight into the role of dopamine D1-like receptor activation on CREB activation, Arc, and BDNF increase, showing that these effects occur temporally and for Arc in subcellular specific sites. This study highlights the dopaminergic system as a critical regulator of subcellular events relevant to neuron plasticity. Future research should address the study of the implications for brain function and behavior.

Development of a Disease Modeling Framework for Glutamatergic Neurons Derived from Neuroblastoma Cells in 3D Microarrays

Neurodegenerative diseases (NDDs) present significant challenges due to limited treatment options, ethical concerns surrounding traditional animal models, and the time-consuming and costly process of using human-induced pluripotent stem cells (iPSCs). We addressed these issues by developing a 3D culture protocol for differentiating SH-SY5Y cells into glutamatergic neurons, enhancing physiological relevance with a 3D microarray culture plate. Our protocol optimized serum concentration and incorporated retinoic acid (RA) to improve differentiation. We analyzed the proportions of N-type and S-type cells, observing that RA in the maturation stage not only reduced cell proliferation but also enhanced the expression of MAP2 and VGLUT1, indicating effective neuronal differentiation. Our approach demonstrates the strong expression of glutamatergic neuron phenotypes in 3D SH-SY5Y neural spheroids, offering a promising tool for high-throughput NDD modeling and advancing drug discovery and therapeutic development. This method overcomes limitations associated with conventional 2D cultures and animal models, providing a more effective platform for NDD research.

Induction of Phosphorylated Tau Accumulation and Memory Impairment by Bisphenol A and the Protective Effects of Carnosic Acid in In Vitro and In Vivo

Bisphenol A (BPA) is a component of polycarbonate plastics that has been implicated in memory impairment. The present study investigated the effect of carnosic acid (CA) on memory deficit induced by BPA and the role of Akt in this mechanism. First, SH-SY5Y cells were treated with 20 nM BPA and 1 μM CA for 12 h. The results showed that treatment of CA with BPA improved the alternation of IRS-1/Akt/GSK-3β as well as the induction of ApoE and Ser396p-tau. Moreover, treatment of CA with BPA restored the signaling involved in long-term potentiation (LTP) effect, leading to induction of synaptic-related proteins, such as PSD-95, synapsin1a, and pro-BDNF. Wortmannin treatment alleviated the reversal by CA. Then, C57BL/6 J male mice were orally administered with CA to test the memory function in BPA treatment. The results showed that CA and RE can improve BPA-induced impairment of motor, recognition, and spatial memory by using open-field test (OFT), novel objective recognition test (NOR), and Y-maze test, respectively. Moreover, CA and RE improved the phosphorylation of tau and the reduction of PSD-95, synapsin1a, and pro-BDNF proteins induced by BPA. Therefore, the results indicated that CA decreased the phosphorylated tau and memory impairment induced by BPA through Akt pathway.

A Novel and Robust Protocol for Differentiation of SH-SY5Y Neuroblastoma Cells into Neuron Like Cells

Introduction

Human neuroblastoma cell line SH-SY5Y is a frequently used experimental cellular model in a variety of neuropsychiatric and neurodegenerative disorders. It is crucial to use a culture protocol that supports the fully differentiation of SH-SY5Y into neuron-like phenotype for the consistency of the results with neurons in vivo. However, a standardized neuronal differentiation protocol for SH-SY5Y cells still does not exist. Numerous differentiation methods have been proposed in the literature, yet SH-SY5Y cells with stronger neuronal characteristics and a more favorable environment for these differentiated cells are required in order to best representation of neurons. Therefore, in the study, we aimed to establish a more successful differentiation protocol for SH-SY5Y cells based on the primary neuron culture technique, which neuronal maturation is very well defined.

Methods

In the study, we rearranged previous SH-SY5Y differentiation protocols, combined them with our primary neuron culture protocol and created a robust and reproducible protocol for differentiation of SH-SY5Y.

Results

Our proposed "retinoic acid+brain-derived neurotrophic factor (RA+BDNF)-induced 7 days differentiation (conalbumin- on day 4) protocol provided well developed neurites, adequate expression and localization of neuronal and synaptic markers resembling mature neurons.

Conclusion

The differentiation protocol we present can enable researchers to obtain satisfactory and properly differentiated SH-SY5Y cells in each independent experiment, achieving the closest possible in vivo results.

Modeling ferroptosis in human dopaminergic neurons: Pitfalls and opportunities for neurodegeneration research

The activation of ferroptosis is being pursued in cancer research as a strategy to target apoptosis-resistant cells. By contrast, in various diseases that affect the cardiovascular system, kidneys, liver, and central and peripheral nervous systems, attention is directed toward interventions that prevent ferroptotic cell death. Mechanistic insights into both research areas stem largely from studies using cellular in vitro models. However, intervention strategies that show promise in cellular test systems often fail in clinical trials, which raises concerns regarding the predictive validity of the utilized in vitro models. In this study, the human LUHMES cell line, which serves as a model for human dopaminergic neurons, was used to characterize factors influencing the activation of ferroptosis. Erastin and RSL-3 induced cell death that was distinct from apoptosis. Parameters such as the differentiation state of LUHMES cells, cell density, and the number and timing of medium changes were identified as determinants of sensitivity to ferroptosis activation. In differentiated LUHMES cells, interventions at mechanistically divergent sites (iron chelation, coenzyme Q10, peroxidase mimics, or inhibition of 12/15-lipoxygenase) provide almost complete protection from ferroptosis. LUHMES cells allowed the experimental modulation of intracellular iron concentrations and demonstrated a correlation between intracellular iron levels, the rate of lipid peroxidation, as well as the sensitivity of the cells to ferroptotic cell death. These findings underscore the importance of understanding the various factors that influence ferroptosis activation and highlight the need for well-characterized in vitro models to enhance the reliability and predictive value of observations in ferroptosis research, particularly when translating findings into in vivo contexts.

Dopamine‑iron homeostasis interaction rescues mitochondrial fitness in Parkinson's disease

Imbalances of iron and dopamine metabolism along with mitochondrial dysfunction have been linked to the pathogenesis of Parkinson's disease (PD). We have previously suggested a direct link between iron homeostasis and dopamine metabolism, as dopamine can increase cellular uptake of iron into macrophages thereby promoting oxidative stress responses. In this study, we investigated the interplay between iron, dopamine, and mitochondrial activity in neuroblastoma SH-SY5Y cells and human induced pluripotent stem cell (hiPSC)-derived dopaminergic neurons differentiated from a healthy control and a PD patient with a mutation in the α-synuclein (SNCA) gene. In SH-SY5Y cells, dopamine treatment resulted in increased expression of the transmembrane iron transporters transferrin receptor 1 (TFR1), ferroportin (FPN), and mitoferrin2 (MFRN2) and intracellular iron accumulation, suggesting that dopamine may promote iron uptake. Furthermore, dopamine supplementation led to reduced mitochondrial fitness including decreased mitochondrial respiration, increased cytochrome c control efficiency, reduced mtDNA copy number and citrate synthase activity, increased oxidative stress and impaired aconitase activity. In dopaminergic neurons derived from a healthy control individual, dopamine showed comparable effects as observed in SH-SY5Y cells. The hiPSC-derived PD neurons harboring an endogenous SNCA mutation demonstrated altered mitochondrial iron homeostasis, reduced mitochondrial capacity along with increased oxidative stress and alterations of tricarboxylic acid cycle linked metabolic pathways compared with control neurons. Importantly, dopamine treatment of PD neurons promoted a rescue effect by increasing mitochondrial respiration, activating antioxidant stress response, and normalizing altered metabolite levels linked to mitochondrial function. These observations provide evidence that dopamine affects iron homeostasis, intracellular stress responses and mitochondrial function in healthy cells, while dopamine supplementation can restore the disturbed regulatory network in PD cells.

Isobolographic Analysis of the Cytoprotective Effect of Dapsone and Cannabidiol Alone or Combination upon Oxygen-Glucose Deprivation/Reoxygenation Model in SH-SY5Y Cells

Oxidative stress and apoptosis cell death are critical secondary damage mechanisms that lead to losing neighboring healthy tissue after cerebral ischemia. This study aims to characterize the type of interaction between dapsone (DDS) and cannabidiol (CBD) and its cytoprotective effect in an in vitro model of oxygen and glucose deprivation for 6 h followed by 24 h of reoxygenation (OGD/R), using the SH-SY5Y cell line. For the combined concentrations, an isobolographic study was designed to determine the optimal concentration-response combinations. Cell viability was evaluated by measuring the lactate dehydrogenase (LDH) release and 3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide (MTT) assays. Also, the reactive oxygen species (ROS) and reduced glutathione (GSH) levels were analyzed as oxidative stress markers. Finally, caspase-3 activity was evaluated as a marker cell death by apoptosis. The results showed a decrease in cell viability, an increase in oxidant stress, and the activity of caspase-3 by the effect of OGD/R. Meanwhile, both DDS and CBD demonstrated antioxidant, antiapoptotic, and cytoprotective effects in a concentration-response manner. The isobolographic study indicated that the concentration of 2.5 µM of DDS plus 0.05 µM of CBD presented a synergistic effect so that in treatment, cell death due to OGD/R decreased. The findings indicate that DDS-CBD combined treatment may be a helpful therapy in cerebral ischemia with reperfusion.

High OXPHOS efficiency in RA-FUdr-differentiated SH-SY5Y cells: involvement of cAMP signalling and respiratory supercomplexes

Neurons are highly dependent on mitochondria to meet their bioenergetic needs and understanding the metabolic changes during the differentiation process is crucial in the neurodegeneration context. Several in vitro approaches have been developed to study neuronal differentiation and bioenergetic changes. The human SH-SY5Y cell line is a widely used cellular model and several differentiation protocols have been developed to induce a neuron-like phenotype including retinoic acid (RA) treatment. In this work we obtained a homogeneous functional population of neuron-like cells by a two-step differentiation protocol in which SH-SY5Y cells were treated with RA plus the mitotic inhibitor 2-deoxy-5-fluorouridine (FUdr). RA-FUdr treatment induced a neuronal phenotype characterized by increased expression of neuronal markers and electrical properties specific to excitable cells. In addition, the RA-FUdr differentiated cells showed an enrichment of long chain and unsaturated fatty acids (FA) in the acyl chain composition of cardiolipin (CL) and the bioenergetic analysis evidences a high coupled and maximal respiration associated with high mitochondrial ATP levels. Our results suggest that the observed high oxidative phosphorylation (OXPHOS) capacity may be related to the activation of the cyclic adenosine monophosphate (cAMP) pathway and the assembly of respiratory supercomplexes (SCs), highlighting the change in mitochondrial phenotype during neuronal differentiation.

Quantifying Morphology of a Differentiating Neuroblastoma Cell Line

SH-SY5Y neuroblastoma cells are a subclone cell line of SK-N-SH cells derived from neural crest that were originally taken from human bone marrow during a biopsy. Research has shown that these cells can be cultured in vitro to differentiate into mature, neuronal phenotypes such as dopaminergic neurons. Here, we added to these discoveries by establishing a quantitative profile for the SH-SY5Y cells of morphometric features including neurite length, branchpoint numbers, and soma area over the span of 18 days. Overall, we showed that in SH-SY5Y cells neurite length initially decreased followed by a dramatic increase of both neurite length and branching. In contrast, soma area for the SH-SY5Y cells initially increased and then stabilized; followed by a small decrease in size. By determining these morphological changes along various timepoints of SH-SY5Y cell development during the programmed cell differentiation process, we provide a set of baseline data for future mechanistic studies in human-derived neuronal cultures.

Neuronal exosomal miRNAs modulate mitochondrial functions and cell death in bystander neuronal cells under Parkinson's disease stress conditions

Parkinson's Disease (PD) is a chronic neurodegenerative disorder characterized by progressive loss of midbrain dopaminergic neurons in the substantia nigra part of the brain. Pathology spread to numerous brain regions and cell types suggests that intercellular communication is essential to PD progression. Exosomes mediate intercellular communication between neurons, glia, and other cell types throughout PD-relevant brain regions. However, the mechanism remains unclear, and its implication in PD pathology, is not well understood. In the current study, we explored the role of exosomes in modulating the response to PD-relevant toxicants. In cellular models of PD, neuronal cell-derived exosomes are readily internalized by recipient neuronal cells as intact vesicles. Internalized exosomes in bystander neuronal cells localize to mitochondria and dysregulate mitochondrial functions, leading to cell death under PD stress conditions. NGS analysis of exosomes released by neuronal cells subjected to PD stress conditions showed that levels of specific miRNAs were altered in exosomes under PD stress conditions. Bioinformatic analysis of the miRNA targets revealed enriched pathways related to neuronal processes and morphogenesis, apoptosis and ageing. Levels of two miRNAs, hsa-miR-30a-5p and hsa-miR-181c-5p, were downregulated in exosomes under PD stress conditions. Expression of the identified miRNAs in neuronal cells led to their enrichment in exosomes, and exosome uptake in neuronal cells ameliorated mitochondrial dysfunction induced by PD stress conditions and rescued cell death. In conclusion, loss of enrichment of specific miRNAs, including miR-30a-5p and miR-181c-5p, under PD stress conditions causes mitochondrial dysfunction and neuronal death, and hence may lead to progression of PD.

Influence of microbially fermented 2´-fucosyllactose on neuronal-like cell activity in an in vitro co-culture system

Scope

2´-Fucosyllactose (2´-FL), the most abundant oligosaccharide in human milk, plays an important role in numerous biological functions, including improved learning. It is not clear, however, whether 2´-FL or a cleavage product could influence neuronal cell activity. Thus, we investigated the effects of 2´-FL, its monosaccharide fucose (Fuc), and microbial fermented 2´-FL and Fuc on the parameters of neuronal cell activity in an intestinal-neuronal transwell co-culture system in vitro.

Methods

Native 13C-labeled 2´-FL and 13C-Fuc or their metabolites, fermented with Bifidobacterium (B.) longum ssp. infantis and B. breve, which were taken from the lag-, log- and stationary (stat-) growth phases of batch cultures, were applied to the apical compartment of the co-culture system with Caco-2 cells representing the intestinal layer and all-trans-retinoic acid-differentiated SH-SY5Y (SH-SY5YATRA) cells mimicking neuronal-like cells. After 3 h of incubation, the culture medium in the basal compartment was monitored for 13C enrichment by using elemental analysis isotope-ratio mass spectrometry (EA-IRMS) and effects on cell viability, plasma, and mitochondrial membrane potential. The neurotransmitter activation (BDNF, GABA, choline, and glutamate) of SH-SY5YATRA cells was also determined. Furthermore, these effects were also measured by the direct application of 13C-2´-FL and 13C-Fuc to SH-SY5YATRA cells.

Results

While no effects on neuronal-like cell activities were observed after intact 2´-FL or Fuc was incubated with SH-SY5YATRA cells, supernatants from the stat-growth phase of 2´-FL, fermented by B. longum ssp. infantis alone and together with B. breve, significantly induced BDNF release from SH-SY5YATRA cells. No such effects were found for 2´-FL, Fuc, or their fermentation products from B. breve. The BDNF release occurred from an enhanced vesicular release, which was confirmed by the use of the Ca2+-channel blocker verapamil. Concomitant with this event, 13C enrichment was also observed in the basal compartment when supernatants from the stat-growth phase of fermentation by B. longum ssp. infantis alone or together with B. breve were used.

Conclusion

The results obtained in this study suggest that microbial products of 2´-FL rather than the oligosaccharide itself may influence neuronal cell activities.

Differentiating SH-SY5Y Cells into Polarized Human Neurons for Studying Endogenous and Exogenous Tau Trafficking: Four Protocols to Obtain Neurons with Noradrenergic, Dopaminergic, and Cholinergic Properties

Pathological alterations of the neuronal Tau protein are characteristic for many neurodegenerative diseases, called tauopathies. To investigate the underlying mechanisms of tauopathies, human neuronal cell models are required to study Tau physiology and pathology in vitro. Primary rodent neurons are an often used model for studying Tau, but rodent Tau differs in sequence, splicing, and aggregation propensity, and rodent neuronal physiology cannot be compared to humans. Human-induced pluripotent stem cell (hiPSC)-derived neurons are expensive and time-consuming. Therefore, the human neuroblastoma SH-SY5Y cell line is a commonly used cell model in neuroscience as it combines convenient handling and low costs with the advantages of human-derived cells. Since naïve SH-SY5Y cells show little similarity to human neurons and almost no Tau expression, differentiation is necessary to obtain human-like neurons for studying Tau protein-related aspects of health and disease. As they express in principle all six Tau isoforms seen in the human brain, differentiated SH-SY5Y-derived neurons are suitable for investigating the human microtubule-associated protein Tau and, for example, its sorting and trafficking. Here, we describe and discuss a general cultivation procedure as well as four differentiation methods to obtain SH-SY5Y-derived neurons resembling noradrenergic, dopaminergic, and cholinergic properties, based on the treatment with retinoic acid (RA), brain-derived neurotrophic factor (BDNF), and 12-O-tetrade canoylphorbol-13-acetate (TPA). TPA and RA-/TPA-based protocols achieve differentiation efficiencies of 40-50% after 9 days of treatment. The highest differentiation efficiency (~75%) is accomplished by a combination of RA and BDNF; treatment only with RA is the most time-efficient method as ~50% differentiated cells can be obtained already after 7 days.

17β-estradiol mitigates the inhibition of SH-SY5Y cell differentiation through WNT1 expression

17β-estradiol (E2) and canonical WNT-signaling represent crucial regulatory pathways for microtubule dynamics and synaptic formation. However, it is unclear yet whether E2-induced canonical WNT ligands have significant impact on neurogenic repair under inflammatory condition. In this study, first, we prepared the chronic activated-microglial-conditioned media, known to be comprised of neuro-inflammatory components. Long term exposure of microglial conditioned media to SH-SY5Y cells showed a negative impact on differentiation markers, microtubule associated protein-2 (MAP2) and synaptophysin (SYP), which was successfully rescued by pre and co-treatment of 10 nM 17β-estradiol. The inhibition of estrogen receptors, ERα and ERβ significantly blocked the E2-mediated recovery in the expression of differentiation marker, SYP. Furthermore, the inflammatory inhibition of canonical signaling ligand, WNT1 was also found to be rescued by E2. To our surprise, E2 was unable to replicate this success with β-catenin, which is considered to be the intracellular transducer of canonical WNT signaling. However, WNT antagonist - Dkk1 blocked the E2-mediated recovery in the expression of the differentiation marker, MAP2. Therefore, our data suggests that E2-mediated recovery in SH-SY5Y differentiation follows a divergent pathway from the conventional canonical WNT signaling pathway, which seems to regulate microtubule stability without the involvement of β-catenin. This mechanism provides fresh insight into how estradiol contributes to the restoration of differentiation marker proteins in the context of chronic neuroinflammation.

Methods used to achieve different levels of the neuronal differentiation process in SH-SY5Y and Neuro2a cell lines: An integrative review

To study the process of neuronal differentiation, the human neuroblastoma (SH-SY5Y) and the murine neuroblastoma (Neuro2a) cell lines have proven to be effective models. For this approach, different protocols involving known neurotrophic factors and other molecules, such as retinoic acid (RA), have been assessed to better understand the neuronal differentiation process. Thus, the goal of this manuscript was to provide a brief overview of recent studies that have used protocols to promote neurodifferentiation in SH-SY5Y and Neuro2a cell lines and used acquired morphology and neuronal markers to validate whether differentiation was effective. The published results supply some guidance regarding the relationship between RA and neurotrophins for SH-SY5Y, as well a serum concentrations for both cell lines. Furthermore, they demonstrate the potential application of Neuro2a, which is critical for future research on neuronal differentiation.

Cellular Lipidome Changes during Retinoic Acid (RA)-Induced Differentiation in SH-SY5Y Cells: A Comprehensive In Vitro Model for Assessing Neurotoxicity of Contaminants

The SH-SY5Y, neuroblastoma cell line, is a common in vitro model used to study physiological neuronal function and the neuronal response to different stimuli, including exposure to toxic chemicals. These cells can be differentiated to neuron-like cells by administration of various reagents, including retinoic acid or phorbol-12-myristate-13-acetate. Despite their common use, there is an incomplete understanding of the molecular changes that occur during differentiation. Therefore, there is a critical need to fully understand the molecular changes that occur during differentiation to properly study neurotoxicity in response to various environmental exposures. Previous studies have investigated the proteome and transcriptome during differentiation; however, the regulation of the cellular lipidome in this process is unexplored. In this work, we conducted liquid chromatography-mass spectrometry (LC-MS)-based untargeted lipidomics in undifferentiated and differentiated SH-SY5Y cells, induced by retinoic acid. We show that there are global differences between the cellular lipidomes of undifferentiated and differentiated cells. Out of thousands of features detected in positive and negative electrospray ionization modes, 44 species were identified that showed significant differences (p-value ≤0.05, fold change ≥2) in differentiated cells. Identification of these features combined with targeted lipidomics highlighted the accumulation of phospholipids, sterols, and sphingolipids during differentiation while triacylglycerols were depleted. These results provide important insights into lipid-related changes that occur during cellular differentiation of SH-5YSY cells and emphasize the need for the detailed characterization of biochemical differences that occur during differentiation while using this in vitro model for assessing ecological impacts of environmental pollutants.

Vibrational spectroscopies for biochemical investigation of X-ray exposure effects on SH-SY5Y human neuroblastoma cells

Neuroblastoma is the most recurring cancer in childhood and adolescence. The SH-SY5Y neuroblastoma cell line is generally adopted for elaborating new therapeutical approaches and/or elaborating strategies for the prevention of central nervous system disturbances. In fact, it represents a valid model system for investigating in vitro the effects on the brain of X-ray exposure using vibrational spectroscopies that can detect early radiation-induced molecular alterations of potential clinical usefulness. In recent years, we dedicated significant efforts in the use of Fourier-transform and Raman microspectroscopy techniques for characterizing such radiation-induced effects on SH-SY5Y cells by examining the contributions from different cell components (DNA, proteins, lipids, and carbohydrates) to the vibrational spectra. In this review, we aim at revising and comparing the main results of our studies to provide a wide outlook of the latest outcomes and a framework for future radiobiology research using vibrational spectroscopies. A short description of our experimental approaches and data analysis procedures is also reported.

Tau-dependent HDAC1 nuclear reduction is associated with altered VGluT1 expression

During AD pathology, Tau protein levels progressively increase from early pathological stages. Tau altered expression causes an unbalance of Tau subcellular localization in the cytosol and in the nuclear compartment leading to synaptic dysfunction, neuronal cell death and neurodegeneration as a consequence. Due to the relevant role of epigenetic remodellers in synaptic activity in physiology and in neurodegeneration, in particular of TRIM28 and HDAC1, we investigated the relationship between Tau and these epigenetic factors. By molecular, imaging and biochemical approaches, here we demonstrate that Tau altered expression in the neuronal cell line SH-SY5y does not alter TRIM28 and HDAC1 expression but it induces a subcellular reduction of HDAC1 in the nuclear compartment. Remarkably, HDAC1 reduced activity modulates the expression of synaptic genes in a way comparable to that observed by Tau increased levels. These results support a competitive relationship between Tau levels and HDAC1 subcellular localization and nuclear activity, indicating a possible mechanism mediating the alternative role of Tau in the pathological alteration of synaptic genes expression.

CRISPR/Cas9-based genome-wide screening of the deubiquitinase subfamily identifies USP3 as a protein stabilizer of REST blocking neuronal differentiation and promotes neuroblastoma tumorigenesis

BACKGROUND

The repressor element-1 silencing transcription factor (REST), a master transcriptional repressor, is essential for maintenance, self-renewal, and differentiation in neuroblastoma. An elevated expression of REST is associated with impaired neuronal differentiation, which results in aggressive neuroblastoma formation. E3 ligases are known to regulate REST protein abundance through the 26 S proteasomal degradation pathway in neuroblastoma. However, deubiquitinating enzymes (DUBs), which counteract the function of E3 ligase-mediated REST protein degradation and their impact on neuroblastoma tumorigenesis have remained unexplored.

METHODS

We employed a CRISPR/Cas9 system to perform a genome-wide knockout of ubiquitin-specific proteases (USPs) and used western blot analysis to screen for DUBs that regulate REST protein abundance. The interaction between USP3 and REST was confirmed by immunoprecipitation and Duolink in situ proximity assays. The deubiquitinating effect of USP3 on REST protein degradation, half-life, and neuronal differentiation was validated by immunoprecipitation, in vitro deubiquitination, protein-turnover, and immunostaining assays. The correlation between USP3 and REST expression was assessed using patient neuroblastoma datasets. The USP3 gene knockout in neuroblastoma cells was performed using CRISPR/Cas9, and the clinical relevance of USP3 regulating REST-mediated neuroblastoma tumorigenesis was confirmed by in vitro and in vivo oncogenic experiments.

RESULTS

We identified a deubiquitinase USP3 that interacts with, stabilizes, and increases the half-life of REST protein by counteracting its ubiquitination in neuroblastoma. An in silico analysis showed a correlation between USP3 and REST in multiple neuroblastoma cell lines and identified USP3 as a prognostic marker for overall survival in neuroblastoma patients. Silencing of USP3 led to a decreased self-renewal capacity and promoted retinoic acid-induced differentiation in neuroblastoma. A loss of USP3 led to attenuation of REST-mediated neuroblastoma tumorigenesis in a mouse xenograft model.

CONCLUSION

The findings of this study indicate that USP3 is a critical factor that blocks neuronal differentiation, which can lead to neuroblastoma. We envision that targeting USP3 in neuroblastoma tumors might provide an effective therapeutic differentiation strategy for improved survival rates of neuroblastoma patients.

Neurite outgrowth induced by stimulation of angiotensin II AT2 receptors in SH-SY5Y neuroblastoma cells involves c-Src activation

Neuroblastoma, the most common extracranial solid tumor occurring in childhood, originates from the aberrant proliferation of neural crest cells. Accordingly, the mechanism underling neuronal differentiation could provide new strategies for neuroblastoma treatment. It is well known that neurite outgrowth could be induced by Angiotensin II (Ang II) AT₂ receptors; however, the signaling mechanism and its possible interaction with NGF (neural growth factor) receptors remain unclear. Here, we show that Ang II and CGP42112A (AT₂ receptor agonist) promote neuronal differentiation by inducing neurite outgrowth and βIII-tubulin expression in SH-SY5Y neuroblastoma cells. In addition, we demonstrate that treatment with PD123319 (AT₂ receptor antagonist) reverts Ang II or CGP42112A-induced differentiation. By using specific pharmacological inhibitors we established that neurite outgrowth induced by CGP42112A requires the activation of MEK (mitogen-activated protein kinase kinase), SphK (sphingosine kinase) and c-Src but not PI3K (phosphatidylinositol 3-kinase). Certainly, CGP42112A stimulated a rapid and transient (30 s, 1 min) phosphorylation of c-Src at residue Y⁴¹⁶ (indicative of activation), following by a Src deactivation as indicated by phosphorylation of Y⁵²⁷. Moreover, inhibition of the NGF receptor tyrosine kinase A (TrkA) reduced neurite outgrowth induced by Ang II and CGP42112A. In summary, we demonstrated that AT₂ receptor-stimulated neurite outgrowth in SH-SY5Y cells involves the induction of MEK, SphK and c-Src and suggests a possible transactivation of TrkA. In that regard, AT₂ signaling pathway is a key player in neuronal differentiation and might be a potential target for therapeutic treatments.

Screening Key Pathogenic Genes and Small Molecule Compounds for PNET

Primitive neuroectodermal tumors (PNET) are rare malignant tumors, but the mortality rate of the patients is extremely high. The aim of this study was to identify the hub genes and pathways involved in the pathogenesis of PNET and to screen the potential small molecule drugs for PNET. We extracted gene expression profiles from the Gene Expression Omnibus database and identified differentially expressed genes (DEGs) through Limma package in R. Two expression profiles (GSE14295 and GSE74195) were downloaded, including 33 and 5 cases separately. Four hundred sixty-eight DEGs (161 upregulated; 307 downregulated) were identified. Functional annotation and KEGG pathway enrichment of the DEGs were performed using DAVID and Kobas. Gene Ontology analysis showed the significantly enriched Gene Ontology terms included but not limited to mitosis, nuclear division, cytoskeleton, synaptic vesicle, syntaxin binding, and GABA A receptor activity. Cancer-related signaling pathways, such as DNA replication, cell cycle, and synaptic vesicle cycle, were found to be associated with these genes. Subsequently, the STRING database and Cytoscape were utilized to construct a protein-protein interaction and screen the hub genes, and we identified 5 hub genes (including CCNB1, CDC20, KIF11, KIF2C, and MAD2L1) as the key biomarkers for PNET. Finally, we identified potential small molecule drugs through CMap. Seven small molecule compounds, including trichostatin A, luteolin, repaglinide, clomipramine, lorglumide, vorinostat, and resveratrol may become potential candidates for PNET drugs.

Assessment of Lab4P Probiotic Effects on Cognition in 3xTg-AD Alzheimer's Disease Model Mice and the SH-SY5Y Neuronal Cell Line

Aging and metabolic syndrome are associated with neurodegenerative pathologies including Alzheimer's disease (AD) and there is growing interest in the prophylactic potential of probiotic bacteria in this area. In this study, we assessed the neuroprotective potential of the Lab4P probiotic consortium in both age and metabolically challenged 3xTg-AD mice and in human SH-SY5Y cell culture models of neurodegeneration. In mice, supplementation prevented disease-associated deteriorations in novel object recognition, hippocampal neurone spine density (particularly thin spines) and mRNA expression in hippocampal tissue implying an anti-inflammatory impact of the probiotic, more notably in the metabolically challenged setting. In differentiated human SH-SY5Y neurones challenged with β-Amyloid, probiotic metabolites elicited a neuroprotective capability. Taken together, the results highlight Lab4P as a potential neuroprotective agent and provide compelling support for additional studies in animal models of other neurodegenerative conditions and human studies.

Maternal pre-eclampsia serum increases neurite growth and mitochondrial function through a potential IL-6-dependent mechanism in differentiated SH-SY5Y cells

Introduction: Pre-eclampsia (PE) is a common and serious hypertensive disorder of pregnancy, which affects 3%-5% of first-time pregnancies and is a leading cause of maternal and neonatal morbidity and mortality. Prenatal exposure to PE is associated with an increased risk of neurodevelopmental disorders in affected offspring, although the cellular and molecular basis of this increased risk is largely unknown. Methods: Here, we examined the effects of exposure to maternal serum from women with PE or a healthy uncomplicated pregnancy on the survival, neurite growth and mitochondrial function of neuronally differentiated human SH-SY5Y neuroblastoma cells, which are commonly used to study neurite growth. Neurite growth and mitochondrial function are two strongly linked neurodevelopmental parameters in which alterations have been implicated in neurodevelopmental disorders. Following this, we investigated the pleiotropic cytokine interleukin-6 (IL-6) levels as a potential mechanism. Results: Cells exposed to 3% (v/v) PE serum for 72 h exhibited increased neurite growth (p < 0.05), which was validated in the human neural progenitor cell line, ReNcell^® VM (p < 0.01), and mitochondrial respiration (elevated oxygen consumption rate (p < 0.05), basal mitochondrial respiration, proton leak, ATP synthesis, and non-mitochondrial respiration) compared to control serum-treated cells. ELISA analysis showed elevations in maternal IL-6 in PE sera (p < 0.05) and placental explants (p < 0.05). In support of this, SH-SY5Y cells exposed to 3% (v/v) PE serum for 24 h had increased phospho-STAT3 levels, which is a key intracellular mediator of IL-6 signalling (p < 0.05). Furthermore, treatment with anti-IL-6 neutralizing antibody blocked the effects of PE serum on neurite growth (p < 0.05), and exposure to IL-6 promoted neurite growth in SH-SY5Y cells (p < 0.01). Discussion: Collectively these data show elevated serum levels of maternal IL-6 in PE, which increases neurite growth and mitochondrial function in SH-SY5Y cells. This rationalizes the further study of IL-6 as a potential mediator between PE exposure and neurodevelopmental outcome in the offspring.

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.

β-II tubulin isotype directs stiffness and differentiation of neuroblastoma SH-SY5Y cells

β-tubulin isotypes regulate the structure and bundling of microtubule (MT) lattice, its dynamics, and resulting functions. They exhibit differential tissue expression, varying due to physical and biochemical cues. In this work, we investigated the effect of transient heat shock at 42 °C on the nuclear and cytoplasmic stiffness of SH-SY5Y neuroblastoma cells through atomic force microscopy. Moreover, the variations in the expression of β-tubulin isotypes as a heat shock response were also monitored. The heat-exposed cells endured a recovery at 37 °C for 24 h and they manifested an increase of cytoplasmic stiffness by 130 ± 25% with respect to untreated controls. The expression of β-II tubulin isotype in heat-recovered cells is augmented by 51 ± 5% whereas the levels of total tubulin and β-III tubulin isotype remain unaltered. Upon depletion of β-II tubulin isotype using shRNA, the increase in cytoplasmic stiffness was dampened. However, it remained unaffected upon depletion with β-III tubulin isotype shRNA. This features the role of the β-II tubulin isotype in regulating cellular stiffness. In addition, neuroblastoma SH-SY5Y cells undergo differentiation by initiating neuritogenesis and prior evidence suggests the indispensable role of β-II tubulin isotype in this process. The heat-recovered cells which expressed higher levels of β-II tubulin isotype expedited the differentiation process in 3-day which was around 5-day for control cells, however, upon depletion of β-II tubulin isotype, the cells almost lost their differentiation potential. Altogether, this work highlights the role of β-II tubulin isotype as a biomarker for cellular stiffness.

Transcriptome Analysis Reveals the Anti-Tumor Mechanism of Eucalyptol Treatment on Neuroblastoma Cell Line SH-SY5Y

Eucalyptol (1.8-cineole), an active component in traditional Chinese medicine Artemisia argyi for moxibustion. Previous studies have shown that eucalyptol has anti-tumor effects on leukemia and colon cancer. Nonetheless, the effect and mechanism of eucalyptol on neuroblastoma remains unclear. In the present study, we intended to reveal the effect and mechanism of eucalyptol treatment on the neuroblastoma cell line SH-SY5Y through transcriptome analysis. In the group treated with eucalyptol, 566 brain genes were up-regulated, while 757 genes were down-regulated. GO function analysis showed that positive regulation of cell cycle was down-regulated in biological processes. Meanwhile, cancer-related pathways were identified in KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis, including pathways in cancer, PI3K-Akt signaling pathway, cAMP signaling pathway, TGF-beta signaling pathway, Hippo signaling pathway, p53 signaling pathway, and additional pathways. Furthermore, we found a key gene, such as MYC, by constructing a network of cancer related pathways with differentially expressed genes and transcription factor analysis. In conclusion, our research indicates that MYC might play a central role in the anit-tumor mechanisms of eucalyptol.

A novel method for generating glutamatergic SH-SY5Y neuron-like cells utilizing B-27 supplement

The human SH-SY5Y neuroblastoma cell line is widely used in neuroscience research as a neuronal cell model. Following differentiation to a neuron-like state, SH-SY5Y cells become more morphologically similar to neurons and form functional synapses. Previous studies have managed to differentiate SH-SY5Y cells towards cholinergic, dopaminergic and adrenergic fates. However, their application in disease modeling remains limited as other neuronal subtypes (e.g., glutamatergic, GABAergic) are also implicated in neurological disorders, and no current protocols exist to generate these subtypes of differentiated SH-SY5Y cells. Our study aimed to evaluate the use of a xeno-free version of B-27, a supplement commonly used in neuronal culture, for SH-SY5Y maintenance and differentiation. To evaluate the proliferative capacity of SH-SY5Y cells cultured in B-27, we performed growth curve analyses, immunocytochemical staining for Ki-67 and qRT-PCR to track changes in cell cycle progression. SH-SY5Y cells cultured in FBS or under serum-starved conditions were used as controls. We observed that SH-SY5Y cells show reduced growth and proliferation rates accompanied by decreased CDK6 and CDK1 expression following 4-day exposure to B-27, suggesting B-27 induces a quiescent state in SH-SY5Y cells. Importantly, this reduced growth rate was not due to increased apoptosis. As cell cycle exit is associated with differentiation, we next sought to determine the fate of SH-SY5Y cells cultured in B-27. B-27-cultured SH-SY5Y cells show changes in cell morphology, adopting pyramidal shapes and extending neurites, and upregulation of neuronal differentiation markers (GAP43, TUBB3, and SYP). B-27-cultured SH-SY5Y cells also show increased expression of glutamatergic markers (GLUL and GLS). These findings suggest that B-27 may be a non-toxic inducer of glutamatergic SH-SY5Y differentiation. Our study demonstrates a novel way of using B-27 to obtain populations of glutamatergic SH-SY5Y cells. As dysregulated glutamatergic signaling is associated with a variety of neuropsychiatric and neurodegenerative disorders, the capability to generate glutamatergic neuron-like SH-SY5Y cells creates endless disease modeling opportunities. The ease of SH-SY5Y culture allows researchers to generate large-scale cultures for high-throughput pharmacological or toxicity studies. Also compatible with the growing popularity of animal-component-free studies, this xeno-free B-27/SH-SY5Y culture system will be a valuable tool to boost the translational potential of preliminary studies requiring glutamatergic neuronal cells of human origin.

The SH-SY5Y human neuroblastoma cell line, a relevant in vitro cell model for investigating neurotoxicology in human: focus on organic pollutants

Investigation of the toxicity triggered by chemicals on the human brain has traditionally relied on approaches using rodent in vivo models and in vitro cell models including primary neuronal cultures and cell lines from rodents. The issues of species differences between humans and rodents, the animal ethical concerns and the time and cost required for neurotoxicity studies on in vivo animal models, do limit the use of animal-based models in neurotoxicology. In this context, human cell models appear relevant in elucidating cellular and molecular impacts of neurotoxicants and facilitating prioritization of in vivo testing. The SH-SY5Y human neuroblastoma cell line (ATCC® CRL-2266^TM) is one of the most used cell lines in neurosciences, either undifferentiated or differentiated into neuron-like cells. This review presents the characteristics of the SH-SY5Y cell line and proposes the results of a systematic review of literature on the use of this in vitro cell model for neurotoxicity research by focusing on organic environmental pollutants including pesticides, 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), flame retardants, PFASs, parabens, bisphenols, phthalates, and PAHs. Organic environmental pollutants are widely present in the environment and increasingly known to cause clinical neurotoxic effects during fetal & child development and adulthood. Their effects on cultured SH-SY5Y cells include autophagy, cell death (apoptosis, pyroptosis, necroptosis, or necrosis), increased oxidative stress, mitochondrial dysfunction, disruption of neurotransmitter homeostasis, and alteration of neuritic length. Finally, the inherent advantages and limitations of the SH-SY5Y cell model are discussed in the context of chemical testing.

TOP2B Is Required to Maintain the Adrenergic Neural Phenotype and for ATRA-Induced Differentiation of SH-SY5Y Neuroblastoma Cells

The neuroblastoma cell line SH-SY5Y is widely used to study retinoic acid (RA)-induced gene expression and differentiation and as a tool to study neurodegenerative disorders. SH-SY5Y cells predominantly exhibit adrenergic neuronal properties, but they can also exist in an epigenetically interconvertible alternative state with more mesenchymal characteristics; as a result, these cells can be used to study gene regulation circuitry controlling neuroblastoma phenotype. Using a combination of pharmacological inhibition and targeted gene inactivation, we have probed the requirement for DNA topoisomerase IIB (TOP2B) in RA-induced gene expression and differentiation and in the balance between adrenergic neuronal versus mesenchymal transcription programmes. We found that expression of many, but not all genes that are rapidly induced by ATRA in SH-SY5Y cells was significantly reduced in the TOP2B null cells; these genes include BCL2, CYP26A1, CRABP2, and NTRK2. Comparing gene expression profiles in wild-type versus TOP2B null cells, we found that long genes and genes expressed at a high level in WT SH-SY5Y cells were disproportionately dependent on TOP2B. Notably, TOP2B null SH-SY5Y cells upregulated mesenchymal markers vimentin (VIM) and fibronectin (FN1) and components of the NOTCH signalling pathway. Enrichment analysis and comparison with the transcription profiles of other neuroblastoma-derived cell lines supported the conclusion that TOP2B is required to fully maintain the adrenergic neural-like transcriptional signature of SH-SY5Y cells and to suppress the alternative mesenchymal epithelial-like epigenetic state.

Functional characterization of the schizophrenia associated gene AS3MT identifies a role in neuronal development

Genome-wide association studies (GWAS) have identified multiple genomic regions associated with schizophrenia, although many variants reside in noncoding regions characterized by high linkage disequilibrium (LD) making the elucidation of molecular mechanisms challenging. A genomic region on chromosome 10q24 has been consistently associated with schizophrenia with risk attributed to the AS3MT gene. Although AS3MT is hypothesized to play a role in neuronal development and differentiation, work to fully understand the function of this gene has been limited. In this study we explored the function of AS3MT using a neuronal cell line (SH-SY5Y). We confirm previous findings of isoform specific expression of AS3MT during SH-SY5Y differentiation toward neuronal fates. Using CRISPR-Cas9 gene editing we generated AS3MT knockout SH-SY5Y cell lines and used RNA-seq to identify significant changes in gene expression in pathways associated with neuronal development, inflammation, extracellular matrix formation, and RNA processing, including dysregulation of other genes strongly implicated in schizophrenia. We did not observe any morphological changes in cell size and neurite length following neuronal differentiation and MAP2 immunocytochemistry. These results provide novel insights into the potential role of AS3MT in brain development and identify pathways through which genetic variation in this region may confer risk for schizophrenia.

Retinoids as anti-cancer agents and their mechanisms of action

Retinoids (vitamin A) have been reported extensively for anti-cancer properties due to their high receptor-binding affinities and gene regulation abilities. However, the anti-cancer potential of retinoids has not been reviewed in recent years. Thus, this review focused on the anti-cancer effects of retinoids and their synergistic effects with other drugs, together with their mechanisms of action in different types of cancers reported in the past five years. The retinoids were well studied in breast cancer, melanoma, and colorectal cancer. Synthetic retinoids have shown higher selectivity, stronger effectiveness, and lower toxicity than endogenous retinoids. Interestingly, the combination treatment of endogenous retinoids with chemotherapy drugs showed enhanced anti-cancer effects. The mechanisms of action reported for retinoids mainly involved the RAR/RXR signaling pathway. However, limited clinical studies were conducted in recent years. Thus, retinoids which are highly potential anti-cancer agents are worth further study in clinical, especially as a combination therapy with chemotherapy drugs.

Naringenin alleviates paraquat-induced dopaminergic neuronal loss in SH-SY5Y cells and a rat model of Parkinson's disease

Parkinson's disease (PD), a common neurodegenerative disease is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. The cause of dopaminergic loss in PD remains unknown for a long time, however, recent reports suggest oxidative stress plays a key role in the pathogenesis of PD. Paraquat (PQ), a widely used herbicide is an oxidative stress inducer that has been implicated as a potential risk factor for the development of PD. Flavonoids are naturally occurring polyphenolic compounds that display a variety of therapeutic properties against oxidative stress. Naringenin (NAR), a natural flavonoid, exhibits neuroprotection against PD-related pathology. However, studies on its neuroprotective role and the underlying mechanisms are scarce, therefore the present study explored the potential neuroprotective role of NAR in PQ-induced parkinsonism in SH-SY5Y cells and rat model. The effect of NAR on PQ-induced cellular toxicity was determined by measuring cell viability, oxidative stress, ATP levels and the same effect was determined by assessing behavioral, biochemical, immunohistochemical, qRT-PCR and Western blot in rat model. NAR treatment in SH-SY5Y cells resulted in increased cell viability, reduced oxidative stress, elevated mitochondrial membrane potential, and higher cellular ATP levels. In rats, NAR treatment resulted in significant neuroprotection against PQ-induced behavioral deficits, oxidative stress, mitochondrial dysfunction, and astrocytosis. NAR treatment significantly modulated PQ-induced mRNA expressions of DRD2, DAT, LRRK2, SNCA, β-catenin, caspase-3, BDNF genes. NAR treatment increased TH protein expression and modulated its immunoreactivity in rat striatum. Also, GFAP decreased in response to NAR treatment. So, in the present study, NAR exhibits neuroprotection against PQ-induced neurotoxicity and neurodegeneration indicating its novel therapeutic potential against PD.

Changes in Biophysical Properties of Undifferentiated SH-SY5Y Cells During Long-term Cultures

The electrophysiological properties of undifferentiated SH-SY5Y cells were examined during cultures prolonged even to 20 days by measuring the passive and active membrane properties at 5 days interval, as well as the spontaneous spiking activity. The results showed that culturing this cell for long time affected not only membrane shape but also their electrophysiological properties. In particular, these cells considerably varied their sodium and potassium voltage-dependent currents, various channels kinetic features and their excitable properties. These modifications would synergically contribute to the bioelectrical conversion of these cells and could be part of a more complex machinery with which the tumoral cell would regulate its survival advantage and resilience. Understanding these processes could add a new clue to the exploitation of this preclinical human neuronal model.

Comparison of SARS-CoV-2 Receptors Expression in Primary Endothelial Cells and Retinoic Acid-Differentiated Human Neuronal Cells

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) is primarily responsible for coronavirus disease (COVID-19) and it is characterized by respiratory illness with fever and dyspnea. Severe vascular problems and several other manifestations, including neurological ones, have also been frequently reported, particularly in the great majority of “long hauler” patients. SARS-CoV-2 infects and replicates in lung epithelial cells, while dysfunction of endothelial and neuronal brain cells has been observed in the absence of productive infection. It has been shown that the Spike protein can interact with specific cellular receptors, supporting both viral entry and cellular dysfunction. It is thus clear that understanding how and when these receptors are regulated, as well as how much they are expressed would help in unveiling the multifaceted aspects of this disease. Here, we show that SH-SY5Y neuroblastoma cells express three important cellular surface molecules that interact with the Spike protein, namely ACE2, TMPRSS2, and NRP1. Their levels increase when cells are treated with retinoic acid (RA), a commonly used agent known to promote differentiation. This increase matched the higher levels of receptors observed on HUVEC (primary human umbilical vein endothelial cells). We also show by confocal imaging that replication-defective pseudoviruses carrying the SARS-CoV-2 Spike protein can infect differentiated and undifferentiated SH-SY5Y, and HUVEC cells, although with different efficiencies. Neuronal cells and endothelial cells are potential targets for SARS-CoV-2 infection and the interaction of the Spike viral protein with these cells may cause their dysregulation. Characterizing RNA and protein expression tempo, mode, and levels of different SARS-CoV-2 receptors on both cell subpopulations may have clinical relevance for the diagnosis and treatment of COVID-19-infected subjects, including long hauler patients with neurological manifestations.

HAGLR promotes neuron differentiation through the miR-130a-3p-MeCP2 axis

Parkinson's disease (PD) is a prevalent neurodegenerative disease. Currently, the molecular mechanisms underlying the progressions of PD are not fully understood. The human neuroblastoma cell line SH-SY5Y has been widely used as an in vitro model for PD. This study aims to investigate the molecular mechanisms of the non-coding RNA-mediated SH-SY5Y differentiation induced by retinoic acid (RA). By microArray analysis, lncRNA HAGLR was observed to be significantly upregulated during the RA-induced SH-SY5Y differentiation. Silencing HAGLR blocked the RA-induced SH-SY5Y differentiation. Moreover, bioinformatical analysis illustrated that miR-130a-3p contains binding sites for HAGLR. The RNA-pull down assay and luciferase assay demonstrated that HAGLR functioned as a ceRNA of miR-130a-3p in SH-SY5Y cells. Overexpression of miR-130a-3p effectively inhibited SH-SY5Y differentiation. We identified MeCP2, a vital molecule in neuronal diseases, to be a direct target of miR-130a-3p in SH-SY5Y cells by western blot and luciferase assays. The rescue experiments verified that recovery of miR-130a-3p in HAGLR-overexpressing SH-SY5Y cells could successfully overcome the RA-induced SH-SY5Y differentiation by targeting MeCP2. In summary, this study reveals a potential molecular mechanism for the lncRNA-HAGLR-promoted in vitro neuron differentiation by targeting the miR-130a-3p-MeCP2 axis, contributing to the understanding of the pathogenesis and progression of PD.

Long-term culture of SH-SY5Y neuroblastoma cells in the absence of neurotrophins: A novel model of neuronal ageing

Background

Studying human ageing is of increasing importance due to the worldwide ageing population. However, it faces the challenge of lengthy experiments to produce an ageing phenotype. Often, to recreate the hallmarks of ageing requires complex empirical conditions that can confound data interpretation. Indeed, many studies use whole organisms with relatively short life spans, which may have little, or limited, relevance to human ageing. There has been extensive use of cell lines to study ageing in human somatic cells, but the modelling of human neuronal ageing is somewhat more complex in vitro.

New Method

We cultured the well-characterised SH-SY5Y human neural cell line to produce high purity cultures of cells differentiated to express a neuronal phenotype, and designed a protocol to maintain these cells in culture until they accumulated biomarkers of cellular ageing.

Results

Our data validate a novel and simple technique for the efficient differentiation and long-term maintenance of SH-SY5Y cells, expressing markers of neuronal differentiation and demonstrating electrical activity in culture. Over time in vitro, these cells progressively accumulate markers of ageing such as enhanced production of reactive oxygen species and accumulation of oxidative damage.

Comparison to Existing Methods

In comparison to existing techniques to model neuronal ageing our method is cost effective, requiring no specialist equipment or growth factors.

Conclusions

We demonstrate that SH-SY5Y cells, grown under these culture conditions, represent a simple model of neuronal ageing that is amenable to cell biological, biochemical and electrophysiological investigation.

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Ageing study is often hindered by the need for complex and lengthy experiments.

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SH-SY5Y cells underwent neuronal differentiation and were cultured until they were of an aged phenotype.

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These cells were electrically active and acquired oxidative damage.

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This is a novel technique to model neuronal ageing in vitro.

ErbB4 mediates amyloid β-induced neurotoxicity through JNK/tau pathway activation: Implications for Alzheimer's disease

Accumulation of amyloid β (Aβ) in the brain is a hallmark of Alzheimer's disease (AD). We previously showed that ErbB4 in parvalbumin (PV)-positive interneurons was associated with Aβ-induced cognitive deficits; however, the underlying mechanism remains undetermined. Here we found that specific deletion of ErbB4 in PV neurons significantly attenuated oligomeric Aβ-induced neuronal toxicity and inhibited Aβ-induced decreases of PSD95 and synaptophysin. Moreover, specific ablation of ErbB4 in PV neurons altered activity-related protein c-Fos and decreased hippocampal PV neurons, especially in the dentate gyrus (DG) of hAPP-J20 mice. Furthermore, c-Jun N-terminal kinase (JNK), a protein downstream of ErbB4, was activated by Aβ but not ErbB4's ligand neuregulin 1 (NRG1) β1, suggesting different downstream pathways for Aβ and NRG1β1. JNK phosphorylation was inhibited by the ErbB4 inhibitor AG1478 and by pretreatment with NRG1β1. More importantly, siRNA knockdown of ErbB4 decreased JNK phosphorylation and expression, tau phosphorylation at Ser396 and Thr 205, and Bax expression. Therefore, ErbB4 might mediate Aβ-induced neuropathology through the JNK/tau pathway and represent a potential therapeutic target in patients with AD.

The effect of caspase-9 in the differentiation of SH-SY5Y cells

Neuroblastoma is the most common solid malignant tumor in infants and young children. Its origin is the incompletely committed precursor cells from the autonomic nervous system. Neuroblastoma cells are multipotent cells with a high potency of differentiation into the neural cell types. Neural differentiation leads to the treatment of neuroblastoma by halting the cell and tumor growth and consequently its expansion. Caspases are a family of proteins involved in apoptosis and differentiation. The present study aimed to investigate the potential role of caspase-9 activation on the differentiation of the human neuroblastoma SH-SY5Y cells. Here we investigated the caspase-9 and 3/7 activity during 1,25-dihydroxycholecalciferol (D3)-mediated differentiation of SH-SY5Y cells and took advantage of the inducible caspase-9 system in putting out the differentiation of the neuroblastoma cells. D3-induced differentiation of the cells could lead to activation of caspase-9 and caspase-3/7, astrocyte-like morphology, and increased expression of Glial fibrillary acidic protein (GFAP). By using the inducible caspase-9 system, we showed differentiation of SH-SY5Y cells to astrocyte-like morphology and increased level of GFAP expression. Furthered studies using a specific caspase-9 inhibitor showed inhibition of differentiation mediated by D3 or caspase-9 to astrocyte-like cells. These results show the potency of caspase-9 to direct differentiation of the human neuroblastoma SH-SY5Y cells into cells showing an astrocyte-like morphology.

NEAT1 polyA-modulating antisense oligonucleotides reveal opposing functions for both long non-coding RNA isoforms in neuroblastoma

Many long non-coding RNAs (lncRNA) are highly dysregulated in cancer and are emerging as therapeutic targets. One example is NEAT1, which consists of two overlapping lncRNA isoforms, NEAT1_1 (3.7 kb) and NEAT1_2 (23 kb), that are functionally distinct. The longer NEAT1_2 is responsible for scaffolding gene-regulatory nuclear bodies termed paraspeckles, whereas NEAT1_1 is involved in paraspeckle-independent function. The NEAT1 isoform ratio is dependent on the efficient cleavage and polyadenylation of NEAT1_1 at the expense of NEAT1_2. Here, we developed a targeted antisense oligonucleotide (ASO) approach to sterically block NEAT1_1 polyadenylation processing, achieving upregulation of NEAT1_2 and abundant paraspeckles. We have applied these ASOs to cells of the heterogeneous infant cancer, neuroblastoma, as we found higher NEAT1_1:NEAT1_2 ratio and lack of paraspeckles in high-risk neuroblastoma cells. These ASOs decrease NEAT1_1 levels, increase NEAT1_2/paraspeckles and concomitantly reduce cell viability in high-risk neuroblastoma specifically. In contrast, overexpression of NEAT1_1 has the opposite effect, increasing cell proliferation. Transcriptomic analyses of high-risk neuroblastoma cells with altered NEAT1 ratios and increased paraspeckle abundance after ASO treatment showed an upregulation of differentiation pathways, as opposed to the usual aggressive neuroblastic phenotype. Thus, we have developed potential anti-cancer ASO drugs that can transiently increase growth-inhibiting NEAT1_2 RNA at the expense of growth-promoting NEAT1_1 RNA. These ASOs, unlike others that degrade lncRNAs, provide insights into the importance of altering lncRNA polyadenylation events to suppress tumorigenesis as a strategy to combat cancer.

A Transient Survival Model of Alteration of Electrophysiological Properties Due to Amyloid Beta Toxicity Based on SH-SY5Y Cell Line

BACKGROUND

Accumulation of toxic strands of amyloid beta (AB), which cause neurofibrillary tangles and, ultimately, cell death, is suspected to be the main culprit behind clinical symptoms of Alzheimer's disease. Although the mechanism of cell death due to AB accumulation is well known, the intermediate phase between the start of accumulation and cell death is less known and investigated, partially due to technical challenges in identifying partially affected cells.

OBJECTIVE

First, we aimed to establish an in vitro model that would show resilience against AB toxicity. Then we used morphological, molecular and electrophysiological assays to investigate how the characteristics of the surviving cells changed after AB toxicity.

METHODS

To investigate this phase, we used differentiation of SH-SY5Y neuroblastoma stem cells by Retinoic Acid (RA) and Brain Derived Neurotrophic Factor (BDNF) to establish an in vitro model which would be able to demonstrate various levels of resistance to AB toxicity. We utilized fluorescent microscopy and whole cell patch clamp recordings to investigate behavior of the model.

RESULTS

We observed significantly higher morphological resilience against AB toxicity in cells which were differentiated by both Retinoic Acid and Brain Derived Neurotrophic Factor compared to Retinoic Acid only. However, the electrophysiological properties of the Retinoic Acid + Brain-Derived Neurotrophic Factor differentiated cells were significantly altered after AB treatment.

CONCLUSION

We established a transient survival model for AB toxicity and observed the effects of AB on transmembrane currents of differentiated neurons.

Exogenous bacterial DnaK increases protein kinases activity in human cancer cell lines

BACKGROUND

Studies of molecular mechanisms underlying tumor cell signaling highlighted a critical role for kinases in carcinogenesis and cancer progression. To this regard, protein kinases regulates a number of critical cellular pathways by adding phosphate groups to specific substrates. For this reason, their involvement in the complex interactions between the human microbiota and cancer cells to determine therapy and tumor progression outcome is becoming increasingly relevant. Mycoplasmas are components of the normal human microbiota, and several species have also been associated to human diseases, including certain cancers. It is also important to note that Mycoplasmas and their proteins are a component of the common tumor microenvironment. In addition, several epidemiological, in vivo and in vitro studies indicate a close involvement of Mycoplasmas in cellular transformation and cancer progression.

METHODS

In this study, we investigate the effect of exogenous Mycoplasma DnaK on kinases activity by treating in vitro four different eukaryotic cancer cell lines, namely lung and prostate cancer, colon adenocarcinoma, and neuroblastoma. Phosphorylation of kinases and specific substrates was measured at 20 and 60 min.

RESULTS

Kinome analysis of our data indicates that Mycoplasma DnaK promotes the dysregulation of the activity of specific kinases and their substrates, with a known involvement in carcinogenesis and cancer progression.

CONCLUSIONS

Given the similarity in structure and amino acid composition of this protein with other bacterial DnaKs we provide a novel mechanism whereby components of the human microbiota and present in the tumor microenvironment are able to deregulate phosphorylation events occurring during carcinogenesis and cancer progression.

Comprehensive Perspectives on Experimental Models for Parkinson's Disease

Parkinson’s disease (PD) ranks second among the most common neurodegenerative diseases, characterized by progressive and selective loss of dopaminergic neurons. Various cross-species preclinical models, including cellular models and animal models, have been established through the decades to study the etiology and mechanism of the disease from cell lines to nonhuman primates. These models are aimed at developing effective therapeutic strategies for the disease. None of the current models can replicate all major pathological and clinical phenotypes of PD. Selection of the model for PD largely relies on our interest of study. In this review, we systemically summarized experimental PD models, including cellular and animal models used in preclinical studies, to understand the pathogenesis of PD. This review is intended to provide current knowledge about the application of these different PD models, with focus on their strengths and limitations with respect to their contributions to the assessment of the molecular pathobiology of PD and identification of the therapeutic strategies for the disease.

Class I HDAC Inhibitor Improves Synaptic Proteins and Repairs Cytoskeleton Through Regulating Synapse-Related Genes In vitro and In vivo

β-amyloid (Aβ) is an important protein molecule in the pathology of Alzheimer’s disease (AD). Accumulation of Aβ leads to the loss of dendritic spines and synapses. These impairments can be ameliorated by histone deacetylase inhibitors (HDACI). However, the mechanisms of HDACIs underlying the effect on synapse are not fully understood. In this study, we examined the relationship between HDAC activity and synapse-related genes and proteins by the administration of a class I HDAC inhibitor, BG45, in the exogenous Aβ-treated cells and mice. Our studies showed that the treatment of HF-488-Aβ_1–42 to SH-SY5Y cells first increased the expression of the postsynaptic dendritic protein (PSD), then decreased it after 36 h. BG45 can alleviate the reduction of the expression of PSD-95 as well as spinophilin and cytoskeletal protein induced by HF-488-Aβ^1–42 aggregation in SH-SY5Y cells. Similar to the results in vitro, PSD-95 in the hippocampus was temporarily increased in the early days of intravenous injection HF-488-Aβ_1–40 to the mice, followed by the decreased expression of PSD-95 on the 9th day. In further studies, for the mice treated with Aβ for 9 days, we found that BG45 decreased the expression of HDAC1 and 2, increased the expression of PSD-95, spinophilin, and synaptophysin (SYP). Our data also showed that BG45 upregulated levels of three synapse-related genes and proteins GRIK2, SCN3B, and SYNPR. These findings suggest that the exogenous Aβ may stimulate transiently the expression of PSD-95 at an early stage, but subsequently contribute to synaptic defects. HDAC1 and 2 are involved in synaptic defects, and BG45 may improve the expression of synaptic and cytoskeletal proteins and repair cytoskeletal damage by specifically inhibiting HDAC1 and 2, thereby modulating synapse-related genes. BG45 might be a potential therapeutic agent for the treatment of an early stage of Aβ-related neurodegenerative disease.

Transformation of SH-SY5Y cell line into neuron-like cells: Investigation of electrophysiological and biomechanical changes

SH-SY5Y human neuroblastoma cells are commonly used as neuronal models. Here, we examined different aspects of SH-SY5Y cell differentiation. Various differentiation protocols have been proposed previously, including treatments with retinoic acid, brain-derived neurotrophic factor (BDNF), cholesterol and oestradiol. We examined undifferentiated SH-SY5Y cells (UNDIFF); cells differentiated by the treatment with retinoic acid (RA); retinoic acid + BDNF (RB); and retinoic acid + BDNF + cholesterol + oestradiol (RBCE). We performed whole-cell patch-clamp recordings from these cells and nanomechanically characterised them by using atomic force microscopy (AFM). Our results indicated that Na⁺ currents become most pronounced in the differentiated RB cells, whereas UNDIFF SH-SY5Y cells had significantly larger K⁺ currents, which is a characteristic feature of cancer cells. AFM observations of these two groups showed that Young's moduli of SH-SY5Y cells increased threefold with differentiation. Furthermore, we showed a direct relationship between Na⁺ channel activity and elasticity in these cells. We conclude that SH-SY5Y human neuroblastoma cells should be used as a neuronal model only when they are differentiated by the treatment with retinoic acid and BDNF.

Refinement of a differentiation protocol using neuroblastoma SH-SY5Y cells for use in neurotoxicology research

Since most models used to study neuronal dysfunction display disadvantages and ethical concerns, a fast and reproducible in vitro model to study mitochondria-related neurodegeneration is required. Here, we optimized and characterized a 3-day retinoic acid-based protocol to differentiate the SH-SY5Y cell line into a neuronal-like phenotype and investigated alterations in mitochondrial physiology and distribution. Differentiation was associated with p21-linked cell cycle arrest and an increase in cell mass and area, possibly associated with the development of neurite-like extensions. Notably, increased expression of mature neuronal markers (neuronal-specific nuclear protein, microtubule-associated protein 2, βIII tubulin and enolase 2) was observed in differentiated cells. Moreover, increased mitochondrial content and maximal area per cell suggests mitochondrial remodeling. To demonstrate that this model is appropriate to study mitochondrial dysfunction, cells were treated for 6 h with mitochondrial toxicants (rotenone, antimycin A, carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) and 6-hydroxydopamine (6-OHDA)). Differentiated cells were more susceptible to increasing concentrations of FCCP, antimycin A, and rotenone, while 6-OHDA showed a distinct dose-dependent neurotoxicity pattern. Even though differentiated cells did not exhibit a fully mature/differentiated neuronal phenotype, the protocol developed can be used to study neurotoxicity processes, mitochondrial dynamics, and bioenergetic impairment, representing an alternative to study mitochondrial impairment-related pathologies in vitro.

Bottom up proteomics identifies neuronal differentiation pathway networks activated by cathepsin inhibition treatment in neuroblastoma cells that are enhanced by concurrent 13-cis retinoic acid treatment

Neuroblastoma is the second most common pediatric cancer involving the peripheral nervous system in which stage IVS metastatic tumors regress due to spontaneous differentiation. 13-cis retinoic acid (13-cis RA) is currently used in the clinic for its differentiation effects and although it improves outcomes, relapse is seen in half of high-risk patients. Combinatorial therapies have been shown to be more effective in oncotherapy and since cathepsin inhibition reduces tumor growth, we explored the potential of coupling 13-cis RA with a cathepsin inhibitor (K777) to enhance therapeutic efficacy against neuroblastoma. Shotgun proteomics was used to identify proteins affected by K777 and dual (13-cis RA/K777) treatment in neuroblastoma SK-N-SH cells. Cathepsin inhibition was more effective in increasing proteins involved in neuronal differentiation and neurite outgrowth than 13-cis RA alone, but the combination of both treatments enhanced the neuronal differentiation effect. SIGNIFICANCE: As neuroblastoma can spontaneously differentiate, determining which proteins are involved in differentiation can guide development of more accurate diagnostic markers and more effective treatments. In this study, we established a differentiation proteomic map of SK-N-SH cells treated with a cathepsin inhibitor (K777) and K777/13-cis RA (dual). Bioinformatic analysis revealed these treatments enhanced neuronal differentiation and axonogenesis pathways. The most affected proteins in these pathways may become valuable biomarkers of efficacy of drugs designed to enhance differentiation of neuroblastoma [1].