Neuron-like Cells Research Articles

Ex vivo disease modelling of Rett syndrome: the transcriptomic and metabolomic implications of direct neuronal conversion.

Rett syndrome (RTT) is a rare neurodevelopmental disorder that primarily affects females and is characterized by a period of normal development followed by severe cognitive, motor, and communication impairment. The syndrome is predominantly caused by mutations in the MECP2. This study aimed to use comprehensive multi-omic analysis to identify the molecular and metabolic alterations associated with Rett syndrome. Transcriptomic and metabolomic profiling was performed using neuron-like cells derived from the fibroblasts of 3 Rett syndrome patients with different MECP2 mutations (R168X, P152R, and R133C) and 1 healthy control. Differential gene expression, alternative splicing events, and metabolite changes were analyzed to identify the key pathways and processes affected in patients with Rett syndrome. Transcriptomic analysis showed there was significant down-regulation of genes associated with the extracellular matrix (ECM) and cytoskeletal components, which was particularly notable in patient P3 (R133C mutation), who had non-random X chromosome inactivation. Additionally, significant changes in microtubule-related gene expression and alternative splicing events were observed, especially in patient P2 (P152R mutation). Metabolomic profiling showed that there were alterations in metabolic pathways, particularly up-regulation of ketone body synthesis and degradation pathways, in addition to an increase in free fatty acid levels. Integrated analysis highlighted the interplay between structural gene down-regulation and metabolic shifts, underscoring the adaptive responses to cellular stress in Rett neurons. The present findings provide valuable insights into the molecular and metabolic landscape of Rett syndrome, emphasizing the importance of combining omic data to enlighten the molecular pathophysiology of this syndrome.

Suppression of PTBP1 in hippocampal astrocytes promotes neurogenesis and ameliorates recognition memory in mice with cerebral ischemia

The therapeutic potential of suppressing polypyrimidine tract-binding protein 1 (Ptbp1) messenger RNA by viral transduction in a post-stroke dementia mouse model has not yet been examined. In this study, 3 days after cerebral ischemia, we injected a viral vector cocktail containing adeno-associated virus (AAV)-pGFAP-mCherry and AAV-pGFAP-CasRx (control vector) or a cocktail of AAV-pGFAP-mCherry and AAV-pGFAP-CasRx-SgRNA-(Ptbp1) (1:5, 1.0 × 1011 viral genomes) into post-stroke mice via the tail vein. We observed new mCherry/NeuN double-positive neuron-like cells in the hippocampus 56 days after cerebral ischemia. A portion of mCherry/GFAP double-positive astrocyte-like glia could have been converted into new mCherry/NeuN double-positive neuron-like cells with morphological changes. The new neuronal cells integrated into the dentate gyrus and recognition memory was significantly ameliorated. These results demonstrated that the in vivo conversion of hippocampal astrocyte-like glia into functional new neurons by the suppression of Ptbp1 might be a therapeutic strategy for post-stroke dementia.

KIT-13, a novel plasmalogen derivative, attenuates neuroinflammation and amplifies cognition.

Plasmalogens (Pls) are specialized phospholipids integral to brain health, whose decline due to aging and stress contributes to cognitive impairment and neuroinflammation. This study explores the potential of a novel Pls derivative, KIT-13 (1-O-octadecyl-2-arachidonoyl-sn-glycerol-3-phosphoethanolamine), in mitigating neuroinflammation and enhancing cognition. When administered to mice, KIT-13 exhibited potent memory enhancement attributed to upregulated brain-derived neurotrophic factor (BDNF), a key player in cognitive processes. In vitro experiments with neuronal cells revealed KIT-13's ability to induce robust cellular signaling, surpassing natural plasmalogens. KIT-13 also promoted neurogenesis and inhibited apoptosis of neuronal-like cells, highlighting its potential in fostering neuronal growth and plasticity. Additionally, KIT-13 treatments reduced pro-inflammatory cytokine expression and attenuated glial activation in the brain. KIT-13's superior efficacy over natural Pls positions it as a promising therapeutic candidate for neurodegenerative conditions such as Alzheimer's disease, characterized by cognitive decline and neuroinflammation. This study presents KIT-13 as an innovative approach for addressing cognitive impairment and neuroinflammatory pathologies.

Chinese Herbs for Inducing Rat Bone Marrow Mesenchymal Stem Cells Differentiated into Neuron-Like Cells

The purpose of this study was to observe the influence of two Chinese herbs of ligustrazine and Xuefuzhuyu injection on neuron-like cells differentiation from rat bone marrow mesenchymal stem cells (BMSCs) respectively. Most primarily cultured BMSCs adhered to the wall at 3 days after cultured, which proliferated faster after passaged, and the 5th passage of cells were mostly purified into BMSCs. In the present study, the 5th passage of BMSCs were (97.51±1.22) % CD44 positive, but negative for CD45, which were identified by immunocytochemical technique. Serum-free low-sugar Dulbecco’s modified Eagle’s medium (L-DMEM) contains 1.25 g/L ligustrazine and 3.0 g/L Xuefuzhuyu injection were used to induce the 5th passage of BMSCs respectively in vitro. Neuron-like cells with prominence and bifurcation could be detected after induction under an inverted phase contrast microscope. The immunocytochemical method showed that nestin and neuron-specific enolase (NSE) were positive in neuron-like cells, but without glial fibrillary acidic protein (GFAP) expression. Both ligustrazine and Xuefuzhuyu injection have the potential for inducing neuron-like cells differentiation from rat bone marrow mesenchymal stem cells respectively. Compared with Xuefuzhuyu injection-induced cells, neuron-like cells induced with ligustrazine might be better in the level of morphological changes, as well as nestin and NSE expression.

A Pro-Inflammatory Stimulus versus Extensive Passaging of DITNC1 Astrocyte Cultures as Models to Study Astrogliosis.

Astrogliosis is a process by which astrocytes, when exposed to inflammation, exhibit hypertrophy, motility, and elevated expression of reactivity markers such as Glial Fibrillar Acidic Protein, Vimentin, and Connexin43. Since 1999, our laboratory in Chile has been studying molecular signaling pathways associated with "gliosis" and has reported that reactive astrocytes upregulate Syndecan 4 and αVβ3 Integrin, which are receptors for the neuronal glycoprotein Thy-1. Thy-1 engagement stimulates adhesion and migration of reactive astrocytes and induces neurons to retract neurites, thus hindering neuronal network repair. Reportedly, we have used DITNC1 astrocytes and neuron-like CAD cells to study signaling mechanisms activated by the Syndecan 4-αVβ3 Integrin/Thy-1 interaction. Importantly, the sole overexpression of β3 Integrin in non-reactive astrocytes turns them into reactive cells. In vitro, extensive passaging is a simile for "aging", and aged fibroblasts have shown β3 Integrin upregulation. However, it is not known if astrocytes upregulate β3 Integrin after successive cell passages. Here, we hypothesized that astrocytes undergoing long-term passaging increase β3 Integrin expression levels and behave as reactive astrocytes without needing pro-inflammatory stimuli. We used DITNC1 cells with different passage numbers to study reactivity markers using immunoblots, immunofluorescence, and astrocyte adhesion/migration assays. We also evaluated β3 Integrin levels by immunoblot and flow cytometry, as well as the neurotoxic effects of reactive astrocytes. Serial cell passaging mimicked the effects of inflammatory stimuli, inducing astrocyte reactivity. Indeed, in response to Thy-1, β3 Integrin levels, as well as cell adhesion and migration, gradually increased with multiple passages. Importantly, these long-lived astrocytes expressed and secreted factors that inhibited neurite outgrowth and caused neuronal death, just like reactive astrocytes in culture. Therefore, we describe two DITNC1 cell types: a non-reactive type that can be activated with Tumor Necrosis Factor (TNF) and another one that exhibits reactive astrocyte features even in the absence of TNF treatment. Our results emphasize the importance of passage numbers in cell behavior. Likewise, we compare the pro-inflammatory stimulus versus long-term in-plate passaging of cell cultures and introduce them as astrocyte models to study the reactivity process.

Piperonal protects neuron-like and retinalpigment epithelial (RPE) cells from oxidative stress and apoptosis through inhibition of α-synuclein aggregation

Protein fibrillation is a crucial process in the onset of several neurodegenerative and retinal disorders due to the formation of cytotoxic species. Because of their capacity to prevent protein aggregation, small molecules have the potential to be appointed as therapeutic agents. Here, we examined the inhibitory impacts of the piperonal as a carbaldehyde-derived compound on the fibrillation process of α-synuclein and underlying cytotoxicity against neuron-like (PC12) and human retinal pigment epithelial (RPE) (ARPE-19) cells. The results showed that the values of kapp and lag time of α-synuclein were modulated with piperonal. Moreover, ANS fluorescence intensity analysis indicated that piperonal can inhibit the formation of a molten global (misfolded) state of α-synuclein, which is a necessary step in the formation of protein amyloid fibrils. Congo red absorption and circular dichroism spectroscopy also verified the inhibition of β-sheet structure formation after treatment of α-synuclein with piperonal. Furthermore, theoretical studies displayed that piperonal interacts with VAL40:HN, GLU35:O, VAL40, and LYS43 amino acid residues and forms a complex. In addition, cytotoxicity assays demonstrated that piperonal as a safe small molecule could mitigate the induced cytotoxicity by α-synuclein amyloids in PC12 and ARPE-19 cells through reduction of ROS and Bax/Bcl2 mRNA overexpression. Taken together, these outcomes showed that piperonal as a natural aldehyde compound can inhibit α-synuclein fibrillation and underlying cytotoxicity which may be developed for potential therapeutic applications in vivo.

Unveiling the double-edged sword: SOD1 trimers possess tissue-selective toxicity and bind septin-7 in motor neuron-like cells

Misfolded species of superoxide dismutase 1 (SOD1) are associated with increased death in amyotrophic lateral sclerosis (ALS) models compared to insoluble protein aggregates. The mechanism by which structurally independent SOD1 trimers cause cellular toxicity is unknown but may drive disease pathology. Here, we uncovered the SOD1 trimer interactome-a map of potential tissue-selective protein-binding partners in the brain, spinal cord, and skeletal muscle. We identified binding partners and key pathways associated with SOD1 trimers and found that trimers may affect normal cellular functions such as dendritic spine morphogenesis and synaptic function in the central nervous system and cellular metabolism in skeletal muscle. We discovered SOD1 trimer-selective enrichment of genes. We performed detailed computational and biochemical characterization of SOD1 trimer protein binding for septin-7. Our investigation highlights key proteins and pathways within distinct tissues, revealing a plausible intersection of genetic and pathophysiological mechanisms in ALS through interactions involving SOD1 trimers.

Trazodone counteracts the response of microglial cells to inflammatory stimuli.

Microglia are resident brain cells that regulate neuronal development and innate immunity. Microglia activation participates in the cellular response to neuroinflammation, thus representing a possible target for pharmacological strategies aimed to counteract the onset and progression of brain disorders, including depression. Antidepressant drugs have been reported to reduce neuroinflammation by acting also on glial cells. Herein, the potential anti-inflammatory and neuroprotective effects of trazodone (TRZ) on the microglial human microglial clone 3 (HMC3) cell line were investigated. HMC3 cells were activated by a double inflammatory stimulus (lipopolysaccharide [LPS] and tumour necrosis factor-alpha [TNF-α], 24 h each), and the induction of inflammation was demonstrated by (i) the increased expression levels of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and ionized calcium-binding adapter molecule 1 (IBA-1), and (ii) the increased release of interleukin 6 (IL-6) and transforming growth factor-beta (TGF-β). TRZ effects were evaluated by treating HMC3 cells for 24 h before (pre-treatment) and after (post-treatment) the double inflammatory stimulus. Notably, TRZ treatments significantly decreased the expression of NF-kB and IBA-1 and the release of the cytokines IL-6 and TGF-β. Moreover, TRZ prevented and reduced the release of quinolinic acid (QUIN), a known neurotoxic kynurenine metabolite. Finally, cellular supernatants collected from microglial cells pre-treated LPS-TNF-α with TRZ were able to improve neuronal-like cell viability, demonstrating a potential neuroprotective effect. Overall, this study suggests the anti-inflammatory effects of TRZ on human microglia and strives for its neuroprotective properties.

Neuroprotective effects of resveratrol through modulation of PI3K/Akt/GSK-3β pathway and metalloproteases.

To analyze the expressional changes in the PI3K/Akt/GSK-3β pathway and metalloprotease in the cellular Alzheimer's Disease (AD) model with the effect of antioxidant resveratrol. Neuron-like cells were obtained by a two-step method of neuronal differentiation by using a combination of retinoic acid (RA) and brain-derived factor (BDNF) exposure. Then, the application of the amyloid beta peptide 25-35 (Aβ25-35) to the cell culture mimicked the environmental toxicity observed in AD. Afterward, cell viability and apoptosis assays were performed to determine whether the resveratrol exerts a cytotoxic and apoptotic effect. Finally, the expressional changes in genes in the cellular AD model with the effect of resveratrol were analyzed by Real-Time PCR. The analysis in silico was assessed using the STRING V12.0 database in each group. Apoptosis data findings were decreased by 1.5-fold and 2.5-fold respectively by Differentiated+Resveratrol (RES) and RES when compared to control but no significant difference was observed between RES and AD model groups. Real-time PCR analysis results revealed PI3K (3.38-fold), AKT (3.95-fold), and RELN (1.99-fold) expressions were significantly higher (p < .001), and also GSK-3β, TAU, ADAMTS-4, ADAMTS-5, and TIMP-3 gene expression levels were significantly downregulated (2.53-, 1.79-, 2.85-, 4.09-, and 6.62-fold, respectively) in the Differentiated+Aβ + RES groups compared to the Differentiated+Aβ group (p < .001). Network analysis shows the functional enrichment of 23 Alzheimer-related GO terms in the Wnt signaling, proteolysis, and extracellular matrix organization pathways. Resveratrol has inhibited GSK-3β by activating the PI3K/Akt insulin pathway in a neurotoxic environment. In addition, TAU, RELN, metalloproteases, and their inhibitors associated with Alzheimer's pathology have been regulated supporting the neuroprotective effect of resveratrol.

Amyloid beta 1-40 and 1-42 fibril ratios and maturation level cause conformational differences with minimal impact on autophagy and cytotoxicity.

The amyloid β (Aβ) peptide has a central role in Alzheimer's disease (AD) pathology. The peptide length can vary between 37 and 49 amino acids, with Aβ1-42 being considered the most disease-related length. However, Aβ1-40 is also found in Aβ plaques and has shown to form intertwined fibrils with Aβ1-42. The peptides have previously also shown to form different fibril conformations, proposed to be related to disease phenotype. To conduct more representative invitro experiments, it is vital to uncover the impact of different fibril conformations on neurons. Hence, we fibrillized different Aβ1-40:42 ratios in concentrations of 100:0, 90:10, 75:25, 50:50, 25:75, 10:90 and 0:100 for either 24 h (early fibrils) or 7 days (aged fibrils). These were then characterized based on fibril width, LCO-staining and antibody-staining. We further challenged differentiated neuronal-like SH-SY5Y human cells with the different fibrils and measured Aβ content, cytotoxicity and autophagy function at three different time-points: 3, 24, and 72 h. Our results revealed that both Aβ1-40:42 ratio and fibril maturation affect conformation of fibrils. We further show the impact of these conformation changes on the affinity to commonly used Aβ antibodies, primarily affecting Aβ1-40 rich aggregates. In addition, we demonstrate uptake of the aggregates by neuronally differentiated human cells, where aggregates with higher Aβ1-42 ratios generally caused higher cellular levels of Aβ. These differences in Aβ abundance did not cause changes in cytotoxicity nor in autophagy activation. Our results show the importance to consider conformational differences of Aβ fibrils, as this can have fundamental impact on Aβ antibody detection. Overall, these insights underline the need for further exploration of the impact of conformationally different fibrils and the need to reliably produce disease relevant Aβ aggregates.

Icariin Ameliorates D-galactose-induced Cell Injury in Neuron-like PC12 Cells by Inhibiting MPTP Opening.

Icariin (ICA) has a good neuroprotective effect and can upregulate neuronal basal autophagy in naturally aging rats. Mitochondrial dysfunction is associated with brain aging-related neurodegenerative diseases. Abnormal opening of the mitochondrial permeability transition pore (mPTP) is a crucial factor in mitochondrial dysfunction and is associated with excessive autophagy. This study aimed to explore that ICA protects against neuronal injury by blocking the mPTP opening and down-regulating autophagy levels in a D-galactose (D-gal)-induced cell injury model. A cell model of neuronal injury was established in rat pheochromocytoma cells (PC12 cells) treated with 200 mmol/L D-gal for 48 h. In this cell model, PC12 cells were pre-treated with different concentrations of ICA for 24 h. MTT was used to detect cell viability. Senescence associated β-galactosidase (SA-β-Gal) staining was used to observe cell senescence. Western blot analysis was performed to detect the expression levels of a senescence-related protein (p21), autophagy markers (LC3B, p62, Atg7, Atg5 and Beclin 1), mitochondrial fission and fusion-related proteins (Drp1, Mfn2 and Opa1), and mitophagy markers (Pink1 and Parkin). The changes of autophagic flow were detected by using mRFP-GFP-LC3 adenovirus. The intracellular ultrastructure was observed by transmission electron microscopy. Immunofluorescence was used to detect mPTP, mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (mtROS) and ROS levels. ROS and apoptosis levels were detected by flow cytometry. D-gal treatment significantly decreased the viability of PC12 cells, and markedly increased the SA-β-Gal positive cells as compared to the control group. With the D-gal stimulation, the expression of p21 was significantly up-regulated. Furthermore, D-gal stimulation resulted in an elevated LC3B II/I ratio and decreased p62 expression. Meanwhile, autophagosomes and autolysosomes were significantly increased, indicating abnormal activation of autophagy levels. In addition, in this D-gal-induced model of cell injury, the mPTP was abnormally open, the ROS generation was continuously increased, the MMP was gradually decreased, and the apoptosis was increased. ICA effectively improved mitochondrial dysfunction to protect against D-gal-induced cell injury and apoptosis. It strongly inhibited excessive autophagy by blocking the opening of the mPTP. Cotreatment with ICA and an mPTP inhibitor (cyclosporin A) did not ameliorate mitochondrial dysfunction. However, the protective effects were attenuated by cotreatment with ICA and an mPTP activator (lonidamine). ICA inhibits the activation of excessive autophagy and thus improves mitochondrial dysfunction by blocking the mPTP opening.

Experimental study on small molecule combinations inducing reprogramming of rat fibroblasts into functional neurons.

To establish a methodological system for reprogramming rat embryonic fibroblasts (REF) into chemically induced neurons (ciNCs) via small molecule compounds to provide safe and effective donor cells for treatment of neurodegenerative diseases. Based on the method established by PEI Gang's research group to directly reprogram human fibroblasts into neurons, the induction medium and maturation medium was optimized by replacing the coating solution, mitigating oxidative stress injury, adding neurogenic protective factors, adjusting the concentration of trichothecenes, performing small-molecule removal experiments, and carrying out immunofluorescence and Western blotting on cells at different stages of induction to validate the effect of induction. When the original protocol was used for induction, the cell survival rate was (34.24±2.77)%. After replacing the coating solution gelatin with matrigel, the cell survival rate increased to (45.41±4.27)%; after adding melatonin, the cell survival rate increased to (67.95±5.61)% and (23.43±1.42)% were transformed into neural-like cells; after adding the small molecule P7C3-A20, the cell survival rate was further increased to (76.27±1.41)%, and (39.72±4.75)% of the cells were transformed into neural-like cells. When the concentration of trichothecene was increased to 30 μmol/L, the proportion of neural-like cells reached (55.79±1.90)%; after the removal of SP600125, (86.96±2.15)% of the cells survived, and the rate of neural-like cell production increased to (63.43±1.60)%. With the optimized protocol, REF could be successfully induced into ciNC through the neural precursor cell stage, in which the neural precursor cells were able to highly express the neural precursor cell markers SRY-related HMG-box gene 2 (Sox2) and paired box 6 (Pax6) as well as neuron-specific marker tubulin 1 (Tuj1), while the expression of fiber-associated protein vimentin was reduced. After two weeks of induction of neural precursor cells in a maturation medium, most cells displayed neuronal-like cell morphology. The induced ciNCs were able to highly express the mature neuronal surface markers Tuj1 and microtubule-associated protein 2 (MAP2), while the expression of vimentin was reduced. The small molecule combinations optimized in this study can reprogram REF to ciNCs under normoxic conditions.

Fast Metabolic Glycan Labeling for Click-Labeling and Imaging of Sialoglycans in Living Acute Brain Slices from Mice and Human Patients.

Living acute brain slices provide a practical platform for imaging sialylation in human brain pathology. However, the limited lifespan of acute brain slices has impeded the use of metabolic glycan labeling (MGL), which requires long-term incubation of clickable unnatural sugars such as N-azidoacetylmannosamine (ManNAz) to metabolically incorporate azides into sialoglycans. Here, we report a fast variant of MGL (fMGL), in which ManNAz-6-phosphate enables efficient azidosugar incorporation within 12 h by bypassing the bottleneck step in the sialic acid biosynthesis pathway, followed by click-labeling with fluorophores and imaging of sialoglycans in acute brain slices from mice and human patients. In the clinical samples of ganglioglioma, fMGL-based imaging reveals specific upregulation of sialylation in astrocyte-like but not neuron-like tumor cells. In addition, fMGL is integrated with click-expansion microscopy for high-resolution imaging of sialoglycans in brain slices. The fMGL strategy should find broad applications in the tissue imaging of glycans and surgical pathology.

Development of an in vitro model of the neurovascular unit for BBB permeability-linked neuroactivity screening

Many potential neurotherapeutic agents fail in the later stages during development due to insufficient blood-brain barrier (BBB) permeability or neurotoxic effects. To address this, we developed an in vitro model incorporating the neurovascular unit (NVU) — astrocytes, pericytes, neurons, and brain microvessel endothelial cells — designed to simulate the in vivo BBB and improve early drug screening. This model uses a direct contact triculture system enhanced by integrating SH-SY5Y neuron-like cells, enabling the study of permeability-linked neuronal responses. Our results show that this expanded NVU model, employing a Transwell® system, enhances the BBB’s restrictive properties and neuronal viability, potentially due to improved cell-cell signaling. Additionally, the model demonstrated increased efflux transporter expression, providing a more physiologically relevant assessment of neuroactivity in relation to BBB permeability. This innovative NVU model offers a predictive and robust tool for evaluating neurotherapeutic agents, facilitating the prioritization of candidates in large compound libraries and potentially reducing attrition rates in drug development. It represents a significant advancement in the methodology for early-stage neurotherapeutic screening, aligning in vitro findings more closely with in vivo responses.

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 6-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 6-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.

Red-Light-Photosensitized Tyrosine 10 Nitration of β-Amyloid1-42 Diverts the Protein from Forming Toxic Aggregates.

Several studies have highlighted the presence of nitration damage following neuroinflammation in Alzheimer's disease (AD). Accordingly, post-transcriptional modifications of β-amyloid (Aβ), including peptide nitration, have been explored as a marker of the disease. However, the implications of Aβ nitration in terms of aggregation propensity and neurotoxicity are still debated. Here, we show new data obtained using a photoactivatable peroxynitrite generator (BPT-NO) to overcome the limitations associated with chemical nitration methods. We found that the photoactivation of BPT-NO with the highly biocompatible red light selectively induces the nitration of tyrosine 10 of freshly solubilized full-length Aβ1-42. Photonitrated Aβ1-42 was, therefore, investigated for aggregation states and functions. It resulted that photonitrated Aβ1-42 did not aggregate into small oligomers but rather self-assembled into large amorphous aggregates. When tested on neuronal-like SH-SY5Y cells and microglial C57BL/6 BV2 cells, photonitrated Aβ1-42 showed to be free of neurotoxicity and able to induce phagocytic microglia cells. We propose that light-controlled nitration of the multiple forms in which Aβ occurs (i.e., monomers, oligomers, fibrils) could be a tool to assess in real-time the impact of tyrosine nitration on the amyloidogenic and toxic properties of Aβ1-42.

Stimulatory effect of eurycomanone from Eurycoma longifolia Jack roots on dopamine secretion in human neuroblastoma SH-SY5Y cell line

Eurycomanone has been identified as the major bioactive compound contributing to Eurycoma longifolia (EL) aphrodisiac activity, however, its mechanism of action remains obscured. Presently, eurycomanone was isolated from EL root extract and its molecular structure was identified. The human neuroblastoma SH-SY5Y cell line was differentiated into human dopaminergic neuron-like cells. Exogenous dopamine levels from the differentiated SH-SY5Y cells were quantified following the treatment of 5, 10, 15 μM of eurycomanone and 10 μM clorgyline as positive control. Dopamine secretion was significantly increased in a dose-dependent manner, compared to the vehicle control (p < .01) in differentiated SH-SY5Y cells. Dopamine concentration stimulated by 15 μM eurycomanone was significantly higher than clorgyline (p < .05), an inhibitor of monoamine oxidase A that suppresses dopamine catabolism. In conclusion, eurycomanone stimulated dopamine release of human SH-SY5Y neuron-like cells, which could be one of the mechanisms that underpin the aphrodisiac properties of the plant.

Sulforaphane Effects on Neuronal-like Cells and Peripheral Blood Mononuclear Cells Exposed to 2.45 GHz Electromagnetic Radiation.

Exposure to 2.45 GHz electromagnetic radiation (EMR) emitted from commonly used devices has been reported to induce oxidative stress in several experimental models. Our study aims to evaluate the efficacy of sulforaphane, a well-known natural product, in preventing radiation-induced toxic effects caused by a 24 h exposure of SH-SY5Y neuronal-like cells and peripheral blood mononuclear cells (PBMCs) to 2.45 GHz EMR. Cells were exposed to radiation for 24 h in the presence or absence of sulforaphane at different concentrations (5-10-25 µg/mL). Cell viability, mitochondrial activity alterations, the transcription and protein levels of redox markers, and apoptosis-related genes were investigated. Our data showed a reduction in cell viability of both neuronal-like cells and PBMCs caused by EMR exposure and a protective effect of 5 µg/mL sulforaphane. The lowest sulforaphane concentration decreased ROS production and increased the Mitochondrial Transmembrane Potential (Δψm) and the NAD+/NADH ratio, which were altered by radiation exposure. Sulforaphane at higher concentrations displayed harmful effects. The hormetic behavior of sulforaphane was also evident after evaluating the expression of genes coding for Nrf2, SOD2, and changes in apoptosis markers. Our study underlined the vulnerability of neuronal-like cells to mitochondrial dysfunction and oxidative stress and the possibility of mitigating these effects by supplementation with sulforaphane. To our knowledge, there are no previous studies about the effects of SFN on these cells when exposed to 2.45 GHz electromagnetic radiation.

SH-SY5Y cells undergo changes in peroxisomal metabolism when exposed to decanoic acid.

Medium-chain fatty acids (MCFAs), particularly decanoic acid (C10) and octanoic acid (C8), have garnered attention in recent years for their potential antiepileptic properties. A previous study from our laboratory demonstrated that C10 targets the PPARγ nuclear receptor, increasing the activity of the antioxidant enzyme catalase and thereby possibly modulating peroxisomal content. Here, we examined markers of peroxisomal content and activity in response to C10 and C8 exposure in neuronal-like SH-SY5Y cells. SH-SY5Y were treated with 250 mM C10 or C8 for a period of 6 days. Following this, biochemical markers of peroxisomal content and function were assessed, including acyl-coA oxidase activity, peroxisomal gene expression and peroxisomal VLCFA β-oxidation. Our findings revealed that C10 treatment augments acyl-CoA oxidase 1 (ACOx1) activity by 129% in comparison to control cells. An exploration into genes related to peroxisomal biosynthesis showed 23% increased expression of PEX11α upon C10 exposure, implying peroxisomal proliferation. Furthermore, it was observed that C10 exposure not only elevated ACOx1 activity but also enhanced peroxisomal β-oxidation of docosanoic acid (C22). Our findings bolster the premise that C10 functions as a peroxisome proliferator, influencing peroxisomal content and function. Further investigations are required to fully understand the mechanistic details as to how this may be beneficial in epilepsy and the potential implications with regards to peroxisomal disease.

RETRACTION: 3-Acetyl-11-Keto-β-Boswellic Acid Attenuated Oxidative Glutamate Toxicity in Neuron-like Cell Lines by Apoptosis Inhibition.

RETRACTION: 3-Acetyl-11-Keto-β-Boswellic Acid Attenuated Oxidative Glutamate Toxicity in Neuron-like Cell Lines by Apoptosis Inhibition.