Neuroprotective effects of polyacrylic acid (PAA) conjugated cerium oxide against hydrogen peroxide- and 6-OHDA-induced SH-SY5Y cell damage

Effects of quercetin-immobilized albumin cerium oxide nanoparticles on glutamate toxicity: in vitro study

One aspect of glutamate (Glut) toxicity may be the opening of the blood-brain barrier to albumin (Al), which in itself can cause nerve cell death. Quercetin (Q) is a polyphenolic substance and has a neuroprotective effect. Cerium oxide nanoparticles (Ce2O3NPs) are highly interested in biological applications due to their antioxidant properties. The current study aimed to investigate the impact of Q-immobilized Al+Ce2O3NPs in Glut-induced neurotoxicity, mainly focusing on cell viability and neurobiochemical changes. Hydrothermal synthesis and characterization of Q-immobilized Al+Ce2O3NPs were performed. After preparing the primary neuron culture, it was exposed to Glut to induce neurotoxicity. Then, various doses of Ce2O3NP, Al+Ce2O3NP, and Q+Al+Ce2O3NPs (1, 5, 10, and 25 µg/ml) were applied to the wells and incubated for 24 h. Then, cell viability was determined by MTT analysis. Additionally, oxidative stress parameters were measured. When the obtained data were examined, it was shown that cell viability decreased with Glut concentration but significantly increased with Q+Al+Ce2O3NPs treatment. When oxidative stress markers were considered, Glut treatment increased LDH, AChE, and TOS levels, while TAC and GSH levels decreased. However, the trend changed after Q+Al+Ce2O3NPs treatment, suggesting that damaged neurons were protected against oxidative stress. The results of this study indicate that Q+Al+Ce2O3NP can ameliorate Glut-induced neurotoxicity, especially when used at a dose of 25 µg/ml.

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

BACKGROUND

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

AIMS AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Protective Effect of Arzanol against H2O2-Induced Oxidative Stress Damage in Differentiated and Undifferentiated SH-SY5Y Cells

Oxidative stress can damage neuronal cells, greatly contributing to neurodegenerative diseases (NDs). In this study, the protective activity of arzanol, a natural prenylated α-pyrone-phloroglucinol heterodimer, was evaluated against the H2O2-induced oxidative damage in trans-retinoic acid-differentiated (neuron-like) human SH-SY5Y cells, widely used as a neuronal cell model of neurological disorders. The pre-incubation (for 2 and 24 h) with arzanol (5, 10, and 25 μM) significantly preserved differentiated SH-SY5Y cells from cytotoxicity (MTT assay) and morphological changes induced by 0.25 and 0.5 mM H2O2. Arzanol reduced the generation of reactive oxygen species (ROS) induced by 2 h oxidation with H2O2 0.5 mM, established by 2',7'-dichlorodihydrofluorescein diacetate assay. The 2 h incubation of differentiated SH-SY5Y cells with H2O2 determined a significant increase in the number of apoptotic cells versus control cells, evaluated by propidium iodide fluorescence assay (red fluorescence) and NucView® 488 assay (green fluorescence). Arzanol pre-treatment (2 h) exerted a noteworthy significant protective effect against apoptosis. In addition, arzanol was tested, for comparison, in undifferentiated SH-SY5Y cells for cytotoxicity and its ability to protect against H2O2-induced oxidative stress. Furthermore, the PubChem database and freely accessible web tools SwissADME and pkCSM-pharmacokinetics were used to assess the physicochemical and pharmacokinetic properties of arzanol. Our results qualify arzanol as an antioxidant agent with potential neuroprotective effects against neuronal oxidative stress implicated in NDs.

Resiquimod Induces C-C Motif Chemokine Ligand 2 Via Nuclear Factor-Kappa B in SH-SY5Y Human Neuroblastoma Cells

Toll-like receptor (TLR) 7 plays an important role in recognizing virus-derived nucleic acids. TLR7 signaling in astrocytes and microglia is critical for activating immune responses against neurotrophic viruses. Neurons express TLR7, similar to glial cells; however, the role of neuronal TLR7 has not yet been fully elucidated. This study sought to determine whether resiquimod, the TLR7/8 agonist, induces the expression of inflammatory chemokines in SH-SY5Y human neuroblastoma cells. Immunofluorescence microscopy revealed that TLR7 was constitutively expressed in SH-SY5Y cells. Stimulation with resiquimod induced C-C motif chemokine ligand 2 (CCL2) expression, accompanied by the activation of nuclear factor-kappa B (NF-κB) in SH-SY5Y cells. Resiquimod increased mRNA levels of C-X-C motif chemokine ligand 8 (CXCL8) and CXCL10, while the increase was slight at the protein level. Knockdown of NF-κB p65 eliminated resiquimod-induced CCL2 production. This study provides novel evidence that resiquimod has promising therapeutic potential against central nervous system viral infections through its immunostimulatory effects on neurons.

Influence of Eu3+ Doping on Physiochemical Properties and Neuroprotective Potential of Polyacrylic Acid Functionalized Cerium Oxide Nanoparticles

Cerium oxide nanoparticles (CeONPs) exhibiting antioxidant properties are investigated as potential tools for neurodegenerative diseases. Here, we synthesized polyacrylic acid conjugated cerium oxide (CeO) nanoparticles, and further to enhance their neuroprotective effect, Eu3+ was substituted at different concentrations (5, 10, 15 and 20 mol%) to the CeO, which can also impart fluorescence to the system. CeONPs and Eu-CeONPs in the size range of 15-30 nm were stable at room temperature. The X-ray Photoelectron Spectroscopy (XPS) analysis revealed the chemical state of Eu and Ce components, and we could conclude that all Eu3+ detected on the surface is well integrated into the cerium oxide lattice. The emission spectrum of Eu-CeO arising from the 7F0 → 5D1 MD and 7F0 → 5D2 transitions indicated the Eu3+ ion acting as a luminescence center. The fluorescence of Eu-CeONPs was visualized by depositing them at the surface of positively charged latex particles. The developed nanoparticles were safe for human neuronal-like cells. Compared with CeONPs, Eu-CeONPs at all concentrations exhibited enhanced neuroprotection against 6-OHDA, while the protection trend of Eu-CeO was similar to that of CeO against H2O2 in SH-SY5Y cells. Hence, the developed Eu-CeONPs could be further investigated as a potential theranostic probe.