Eukaryotic elongation factor 1-alpha-2 (eEF1A2) is a neuron- and muscle-specific translation elongation factor isoform that supports high-demand proteostasis in terminally differentiated cells. Beyond its canonical role in translation elongation, eEF1A2 participates in noncanonical processes linked to actin cytoskeleton regulation, compartmentalized/local translation, and stress-response signaling. A central challenge in the field is that the strength and type of evidence implicating eEF1A2 differ substantially across disease classes. In neurodevelopmental disorders, heterozygous de novo pathogenic variants in EEF1A2 provide strong causal human genetic evidence for developmental and epileptic encephalopathies and related phenotypes, supported by functional studies showing reduced de novo protein synthesis/elongation and altered actin bundling in common patient-associated variants. In contrast, in neurodegenerative paradigms (e.g., toxin-based Parkinson's disease models and ischemia-reperfusion injury), eEF1A2 is primarily implicated as a contributory node within oxidative stress, autophagy/mitophagy, and inflammatory signaling pathways, largely based on cellular and animal model evidence rather than Mendelian causality. This review adopts an evidence-based framework and organizes findings around a unified mechanistic model connecting canonical elongation and noncanonical cytoskeleton/stress/autophagy functions to neuronal phenotypes. Collectively, current evidence supports a causal role for eEF1A2 in neurodevelopmental disorders but only a contributory role in neurodegenerative conditions.

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons, primarily due to mitochondrial dysfunction. Current treatments focus on managing symptoms but are unable to regenerate neurons. Human dental pulp stem cells (hDPSCs) offer a promising source for neurodegenerative therapy due to their accessibility and neuro-supportive properties. However, research on the mitochondrial characteristics of hDPSCs and their therapeutic potential remains limited. This study investigates the capacity of mitochondria isolated from hDPSCs to restore mitochondrial function and promote neuronal recovery and function in a PD cellular model. hDPSCs were isolated and characterized for mesenchymal stem cell properties. Mitochondria were isolated, quantified, and assessed for viability and morphology using MitoTracker staining and transmission electron microscopy. Mitochondrial uptake and functional recovery were evaluated in a PD cellular model using MPP⁺-treated differentiated SH-SY5Y cells. Mitochondrial function was assessed by measuring Complex I activity, ATP production, and reactive oxygen species (ROS) levels. Neuroregeneration and synaptic function were analyzed through neurite length, growth-associated protein 43 (GAP43) and tyrosine hydroxylase (TH), Synaptophysin (SYP), dopamine transporter (DAT), calcium imaging, and mitochondrial dynamics. Isolated hDPSC-derived mitochondria were mostly viable, spherical, and displayed immature cristae. In MPP⁺-treated SH-SY5Y cells, mitochondrial transfer restored Complex I activity, elevated ATP production, and reduced ROS. Treated cells also showed significantly longer neurites and increased expression of GAP43, TH, SYP, and DAT. Calcium imaging revealed restored intracellular calcium responses upon stimulation. Mitochondria from hDPSCs localized in both cell bodies and neurites and remained distinct from damaged host mitochondria, supporting synaptic function. Mitochondria derived from hDPSCs can restore bioenergetic function, reduce oxidative stress, and promote structural and functional recovery in a PD cellular model. These findings highlight the foundational therapeutic potential of hDPSC-derived mitochondria as a regenerative approach for neurodegenerative diseases.

Background:Parkinson's disease (PD) is a progressive neurodegenerative disorder. PD patients mostly exhibit mitochondrial dysfunction and autophagic impairment. Asiatic acid (AA) is a triterpenoid with the highest antioxidant activity used to treat oxidative stress. It has been found to have a neuroprotective effect against mitochondrial dysfunction in cellular models of PD; however, its effect on autophagy has not been investigated. Purpose:This study aimed to investigate whether AA affects autophagy in a cellular model of PD. Methods:SH-SY5Y cells were differentiated into dopaminergic neuron-like cells via retinoic acid administration. Differentiated cells were treated with AA for 24 h and then exposed to 1-methyl-4-phenylpyridinium (MPP+). Cell viability was assessed using a 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. The expression of microtubule-associated protein 1 light chain 3 (LC3)-II/I, Beclin-1, sequestosome-1/ubiquitin-binding protein p62 (SQSTM1/p62), and tyrosine hydroxylase (TH) was analyzed via Western blot. Caspase-3/7 and LC3 expression was measured using immunofluorescence, as was the colocalization of LC3 and mitochondria. MitoTracker and JC-10 were used to assess the mitochondrial morphology and mitochondrial membrane potential (ΔΨm), respectively. Results:Pretreating cells with AA before MPP+ exposure resulted in significantly higher expression of LC3-II/I and Beclin-1, while the expression of SQSTM1/p62 was slightly lower compared to that in cells not pretreated with AA. Cells pretreated with AA exhibited significantly higher viability and TH expression, but significantly lower caspase-3/7 expression and numbers of apoptotic nuclei compared to cells treated with MPP+ alone. Notably, pretreatment with AA resulted in tubular mitochondria with considerably higher ΔΨm values. The colocalization of LC3 and mitochondria was also significantly higher in the cells pretreated with AA. Conclusion:AA protected dopaminergic neuron-like cells against MPP+-induced apoptosis via the induction of autophagy and the enhancement of mitochondrial function, suggesting that it could be developed as a therapeutic agent for PD.

Alpha-mangostin (α-M), a xanthone derivative with known antioxidative properties, has demonstrated a protective effect on neurons under oxidative stress, a key factor in the pathogenesis of Parkinson’s disease (PD). However, its impact on mitochondrial integrity and autophagy in PD remains insufficiently understood. Therefore, the present study aimed to investigate the role of α-M in regulating defective mitochondrial proteins and its influence on the mTOR pathway, both of which are critical in the regulation of autophagy. This study investigated the effects of α-M pretreatment on 1-methyl-4-phenylpyridinium (MPP+)-induced neurotoxicity in SH-SY5Y dopaminergic neurons. MPP+, a mitochondrial complex I inhibitor, significantly reduced the expression of mitochondrial proteins NDUFS3 and TIMM23, induced mitochondrial damage, and triggered excessive autophagy, as evidenced by elevated LC3-II/LC3-I ratio and phospho-Beclin-1 expression. These changes were accompanied by dysregulation of the mTOR signaling pathway, including increased phosphorylation of mTOR and suppression of its downstream effector p70S6K. α-M pretreatment restored NDUFS3 and TIMM23 levels, preserved mitochondrial morphology and membrane potential, and reduced autophagy activation by mitigating MPP+-induced LC3B accumulation and Beclin-1 activation. Additionally, α-M restored balance in the mTOR signaling pathway by reducing mTOR phosphorylation and restoring p70S6K activity, counteracting the autophagic dysregulation caused by MPP+. Importantly, α-M exhibited no toxicity under normal conditions, indicating its protective effects are context-dependent and activated only during cellular stress. These findings highlight the potential of α-M as a therapeutic agent for PD, providing neuroprotection through its targeted modulation of mitochondrial proteins and mTOR signaling that regulates autophagy.

OBJECTIVE:To investigate the effects of asiaticoside (AS) and asiatic acid (AA) against radiotherapy on neural stem cells induced from human stem cells from apical papilla (NSCs-hSCAPs) through dose-reduction factor (DRF) evaluation and their radiosensitization on human neuroblastoma SH-SY5Y cells. METHODS:NSCs-hSCAPs were treated with AS or AA (0-500 μM) and radiation (0-8 Gy). Isolated hSCAPs were verified mesenchymal stem cells (MSCs) properties according to standard protocol. Subsequently, NSCs-hSCAPs were characterized by Cresyl violet staining and immunocytochemistry. A culture plate containing the cells was embedded into the solid water and bolus phantom. After CT simulation and treatment planning, dose uniformity to the plate was evaluated. X-ray, AS, and AA toxicity were investigated using cell viability (MTT) assay. Finally, DRF50 was calculated from dose-response curves at 50% cell viability for both cell lines. RESULTS:hSCAPs presented MSCs markers. NSCs-hSCAPs were successfully generated due to the Nissl substance, Nestin, and SOX2 positively stained. Dose homogeneity was represented as isodose at 100% covered the cells in the phantom, suggesting that they were received according to prescribed doses. MTT results revealed that AA was more toxic than AS in both cells. X-ray reduced significantly in a number of tested cells and more radiosensitivity was observed in SH-SY5Y. However, the reduction affected by 4 Gy was diminished after AA or AS at 2 μM applied to NSCs-hSCAPs. Moreover, a significant increase of DRF50 was found at 2 μM of AA (6.72 ± 2.35) and AS (3.84 ± 1.41) in NSCs-hSCAPs whereas it did not show in SH-SY5Y. Interestingly, 20 μM AA could reduce SH-SY5Y cell viability (mean of the cell viability (%) was 25.22 ± 1.53 compared to 30.22 ± 1.46 in the control group), showing a very large in terms of its effect size (Cohen's d value = 1.37). CONCLUSION:AA and AS had a specific radioprotective effect on NSCs-hSCAPs without affecting SH-SY5Y. However, AA might be a better therapeutic agent due to expressing a lethal effect on the irradiated cancer cells.

Background and purpose:Oxidative stress plays an important role in Alzheimer's disease (AD) pathogenesis. Moringa oleifera leaf (MOL) extract has been shown to have antioxidant activities. Here, we studied the antioxidative and anti-apoptotic effects of water-soluble MOL extract in an amyloid beta (Aβ)-induced oxidative stress model of AD. Experimental approach:The effect of amyloid beta (Aβ)1-42 and MOL extract on differentiated SH-SY5Y cell viability was assessed by MTT assay. Cells were treated with Aβ1-42, MOL extract, or MOL extract followed by Aβ1-42. The mitochondrial membrane potential (ΔΨm) and the reactive oxygen species (ROS) were evaluated by flow cytometry and dihydroethidium (DHE) assay, respectively. Western blotting was used to assess the expression of mitochondrial proteins TIMM23 and NDUFS3, apoptosis-related proteins Bax, Bcl-2, and cleaved caspase-3 along with fluorescence analysis of caspase-3/7, and Akt phosphorylation. Findings/Results:MOL extract pretreatment at 25, 50, and 100 μg/mL prevented ΔΨm reduction. At 100-μg/mL, MOL extract decreased TIMM23 and NDUFS3 proteins and DHE signals in Aβ1-42-treated cells. MOL extract pretreatment (25, 50, and 100 μg/mL) also alleviated the apoptosis indicators, including Bax, caspase-3/7 intensity, and cleaved caspase-3, and increased Bcl-2 levels in Aβ1-42-treated cells, consistent with a reduction in the number of apoptotic cells. The protective effects of MOL extract were possibly mediated through Akt activation, evidenced by increased Akt phosphorylation. Conclusion and implications:The neuroprotective effect of MOL extract could be mediated via the activation of Akt, leading to the suppression of oxidative stress and apoptosis in an Aβ1-42 model of AD.

Central neurocytoma (CN) is a rare intraventricular tumor. The common presenting symptoms of CN are headache, vomiting, and visual disturbance, which results from increased intracranial pressure. This report presents a case of CN with unusual clinical presentations. A 25-year-old female with CN presented with a one-day history of unilateral headache, ipsilateral periorbital pain, multifocal paresthesias, and vomiting. Magnetic resonance images showed an intraventricular mass with a soap-bubble appearance and numerous cystic areas typical for CN, causing obstructive hydrocephalus and a midline shift. After one night of rest, her headache, periorbital pain, and paresthesias disappeared. It is possible that the tumor could be mobile with regard to the patient's head position, causing occasional obstruction of the foramen of Monro. Due to the tumor size, which was larger than 4 centimeters, the surgical approach with either gross tumor resection or subtotal resection plus adjuvant radiotherapy should be carefully considered.

The tissue-specific protein eEF1A2 has been linked to the development of neurological disorders. The role of eEF1A2 in the pathogenesis of Parkinson’s disease (PD) has yet to be investigated. The aim of this study was to determine the potential neuroprotective effects of eEF1A2 in an MPP+ model of PD. Differentiated SH-SY5Y cells were transfected with eEF1A2 siRNA, followed by MPP+ exposure. The expression of p-Akt1 and p-mTORC1 was determined using Western blotting. The expression of p53, Bax, Bcl-2, and caspase-3 was evaluated using qRT-PCR. Cleaved caspase-3 levels and Annexin V/propidium iodide flow cytometry were used to determine apoptosis. The effects of PI3K inhibition were examined. The results showed that eEF1A2 siRNA significantly reduced the eEF1A2 expression induced by MPP+. MPP+ treatment activated Akt1 and mTORC1; however, eEF1A2 knockdown suppressed this activation. In eEF1A2-knockdown cells, MPP+ treatment increased the expression of p53 and caspase-3 mRNA levels as well as increased apoptotic cell death when compared to MPP+ treatment alone. In cells exposed to MPP+, upstream inhibition of the Akt/mTOR pathway, by either LY294002 or wortmannin, inhibited the phosphorylation of Akt1 and mTORC1. Both PI3K inhibitors increased eEF1A2 expression in cells, whether or not they were also treated with MPP+. In conclusion, eEF1A2 may function as a neuroprotective factor against MPP+, in part by regulating the Akt/mTOR pathway upstream.

Medical teachers need training in medical education to improve their teaching skills, keep up with modern teaching methods, and promote student-centered learning. Multiple methods exist for training medical teachers in the area of medical education. The SOLO (Structure of the Observed Learning Outcome) taxonomy can be included in training medical teachers. The SOLO taxonomy has five levels, which is used as a framework for assessing depth of understanding and the complexity of a learner’s response to a question. Here, the author constructed two questions in the field of medical education and provided examples of answers related to each level of understanding in the SOLO taxonomy. A medical educator can employ the SOLO taxonomy to conduct a qualitative analysis of the level of understanding of medical teachers and can use this understanding to design training activities that promote higher levels of thinking and understanding. Additionally, the SOLO taxonomy can be used to improve the effectiveness of training strategies, as well as to provide targeted feedback to medical teachers.

Metformin (MET) and rapamycin (RAPA) have been reported to protect against neurodegeneration in cellular and animal models of Parkinson's disease (PD). MET, which is a first-line drug for type 2 diabetes, and RAPA are known as mTORC1 inhibitors. MET also acts as an AMPK activator, which leads to the inhibition of mTORC1 activity. mTORC1 is a downstream target of Akt signaling. Inactivation of Akt/mTORC1 and its downstream S6K1 can promote autophagy, a process involved in PD pathogenesis. Based on their mechanisms and potential benefits, we evaluated the potential protective effect of pretreatment with combinations of MET and RAPA in a 1-methyl-4-phenylpyridinium ion (MPP+)-treated SH-SY5Y neuronal cell model of PD. The results showed that MET and RAPA combinations lowered cell viability after exposure to MPP+. Increased LC3-II levels by MPP+ were not altered by MET and RAPA pretreatment. In normal neuronal cells, MET and RAPA pretreatment inhibited the phosphorylation of both Akt and S6K1, and the phosphorylation remained suppressed after MPP+ exposure. These findings suggest that when cells were exposed to MPP+, suppressed phosphorylation of both Akt and S6K1 by the MET and RAPA combination may lead to an inappropriate autophagic response, resulting in increased cell death.

Myasthenia gravis (MG) is an autoimmune disorder characterized by abnormal neuromuscular transmission. The thymus is believed to play a key role in the pathogenesis of MG, and thymectomy has been an optional treatment for the disease. Relapse of MG after thymectomy has been reported. Exacerbations and new onset of MG following COVID-19 vaccination have also been documented. This report presents a case of a stable MG patient with recent COVID-19 vaccination experiencing flare-ups of symptoms shortly after video-assisted thoracoscopic (VATS) thymectomy. A 31-year-old female received the second dose of the BNT162b2 mRNA COVID-19 vaccine eight days before thymectomy and developed flare-ups of symptoms four days after the surgery. Although the substantial link between MG exacerbations post-thymectomy and pre-thymectomy COVID-19 vaccination cannot be concluded, this observation warrants further research.

Objectives The translation elongation factor-1, alpha-2 (eEF1A2) plays an important role in protein synthesis. Mutations in this gene have been described in individuals with neurodevelopmental disorders. Here, we silenced the expression of eEFA2 in human SH-SY5Y neuroblastoma cells and observed its roles in neuronal proliferation and differentiation upon induction with retinoic acid. Methods eEF1A2 were silenced using siRNA transfection. Cell proliferation was qualitatively evaluated by Ki-67 immunocytochemistry. Neuronal differentiation was induced with retinoic acid for 3, 5, 7 and 10 days. Neurite length was measured. The expression of microtubule-associated protein 2 (MAP2) was analyzed by western blotting. Tyrosine hydroxylase expression was visualized by immunofluorescence. Cytotoxicity to a neurotoxin, 1-methyl-4-phenylpyridinium (MPP+), was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and western blotting of cleaved caspase-3. Results eEF1A2 knockdown suppressed the proliferative activity of undifferentiated SH-SY5Y cells as shown by decreased Ki-67 immunostaining. Upon retinoic acid-induction, differentiated neurons with eEF1A2 knockdown exhibited shorter neurite length than untransfected cells, which was associated with the reduction of tyrosine hydroxylase and suppression of MAP2 at 10 days of differentiation. eEF1A2 knockdown decreased the survival of neurons, which was clearly observed in undifferentiated and short-term differentiated cells. Upon treatment with MPP+, cells with eEF1A2 knockdown showed a further reduction in cell survival and an increase of cleaved caspase-3 protein. Conclusions Our results suggest that eEF1A2 may be required for neuronal proliferation and differentiation of SH-SY5Y cells. Increased cell death susceptibility against MPP+ in eEF1A2-knockdown neurons may imply the neuroprotective role of eEF1A2.

Background The protein kinase B/mammalian target of the rapamycin (Akt/mTOR) pathway is one of the most potent prosurvival signaling cascades that is constitutively active in neuroblastoma. The eukaryotic translation elongation factor-1, alpha-2 (eEF1A2) protein has been found to activate the Akt/mTOR pathway. However, there is a lack of data on the role of eEF1A2 in neuroblastoma. The present study investigated the effect of eEF1A2 silencing on the viability of neuroblastoma cells and its possible signaling. Materials and Methods: Human SH-SY5Y neuroblastoma cells were transfected with small interfering RNA (siRNA) against eEF1A2. After 48 h of transfection, cell viability was assessed using an MTT assay. The mRNA expression of p53, Bax, Bcl-2, caspase-3 and members of the phosphoinositide 3-kinases (PI3K)/Akt/mTOR pathway was determined using quantitative real-time RT-PCR (qRT-PCR). The protein expression of Akt and mTOR was measured using Western blot analysis. Results: eEF1A2 knockdown significantly decreased the viability of neuroblastoma cells. No significant changes were observed on the expression of p53, Bax/Bcl-2 ratio, and caspase-3 mRNAs; however, the upregulated trends were noted for the p53 and Bax/Bcl-2 ratio. eEF1A2 knockdown significantly inhibited the phosphorylation of both Akt and mTOR. Almost all of the class I (PIK3CA, PIK3CB, and PIK3CD) and all of the class II PI3K genes were slightly increased in tumor cells with eEF1A2 knockdown. In addition, a slightly decreased expression of the Akt2, mTORC1, and mTORC2 was observed. Conclusion: eEF1A2 knockdown induced neuroblastoma cell death, in part through the inhibition of Akt and mTOR, suggesting a potential role of eEF1A2 as a molecular target for neuroblastoma therapy.

1-Methyl-4-phenylpyridinium ion (MPP+) is widely used to induce a cellular model of Parkinson's disease (PD) in dopaminergic cell lines. Downregulation of the protein translation elongation factor 1 alpha (eEF1A) has been reported in the brain tissue of PD patients. eEF1A2, an isoform of eEF1A, is associated with lysosome biogenesis that involves the autophagy process. However, the role of eEF1A2 on autophagic activity in PD has not been elucidated. In this work, we investigated the role of eEF1A2 on autophagy using eEF1A2 siRNA knockdown in differentiated SH-SY5Y neuronal cells treated with MPP+. We found that eEF1A2 was upregulated in differentiated cells, which could be silenced by eEF1A2 siRNA. Significantly, cells treated with MPP+ after eEF1A2 knockdown showed a decreased number of LC3 puncta, decreased LC3-II/LC3-I ratio, and decreased phospho-Beclin-1, compared to the MPP+ alone group. These cells showed extensive areas of mitochondria damage, with a reduction of mitochondrial membrane potential, but reduced mitophagy as indicated by the reduced colocalization of LC3 puncta with damaged mitochondria. Cells with eEF1A2 siRNA plus MPP+ treatment aggravated α-synuclein accumulation but reduced colocalization with LC3. As a result, eEF1A2 knockdown decreased viability, increased apoptotic nuclei, increased caspase-3/7 activation and increased cleaved caspase-3 when cells were treated with MPP+. These results suggest that eEF1A2 is essential for dopaminergic neuron survival against MPP+, in part through autophagy regulation.

Parkinson's disease (PD) is a neurodegenerative disorder that affects movement, and its development is associated with environmental and genetic factors. Genetic variants in GBA and PARK2 are important risk factors implicated in the development of PD; however, their precise roles have yet to be elucidated. The present study aimed to identify and analyse proteins from the skin fibroblasts of patients with PD carrying heterozygous GBA and PARK2 variants, and from healthy controls. Liquid chromatography coupled with tandem mass spectrometry and label-free quantitative proteomics were performed to identify and compare differential protein expression levels. Moreover, protein-protein interaction networks were assessed using Search Tool for Retrieval of Interacting Genes analysis. Using these proteomic approaches, 122 and 119 differentially expressed proteins from skin fibroblasts of patients with PD carrying heterozygous GBA and PARK2 variants, respectively, were identified and compared. According to the results of protein-protein interaction and Gene Ontology analyses, 14 proteins involved in the negative regulation of macromolecules and mRNA metabolic processes, and protein targeting to the membrane exhibited the largest degree of differential expression in the fibroblasts of patients with PD with a GBA variant, whereas 20 proteins involved in the regulation of biological quality, NAD metabolic process and cytoskeletal organization exhibited the largest degree of differential expression in the fibroblasts of patients with PD with a PARK2 variant. Among these, the expression levels of annexin A2 and tubulin β chain, were most strongly upregulated in the fibroblasts of patients with GBA-PD and PARK2-PD, respectively. Other predominantly expressed proteins were confirmed by western blotting, and the results were consistent with those of the quantitative proteomic analysis. Collectively, the results of the present study demonstrated that the proteomic patterns of fibroblasts of patients with PD carrying heterozygous GBA and PARK2 variants are different and unique. Aberrant expression of the proteins affected by these variants may reflect physiological changes that also occur in neurons, resulting in PD development and progression.

AIM:eEF1A2 is highly expressed in postmitotic cells and has been reported to interact with the antioxidant enzyme peroxiredoxin 1 (PRDX1). PRDX1 is involved in motor neuron differentiation. Here, we studied the relationship between eEF1A2 and PRDX1 during dopaminergic neuron differentiation, and examined their possible association in an oxidative stress model of Parkinson's disease (PD).MAIN METHODS:Expression of eEF1A2 and PRDX1 in SH-SY5Y cells at various durations of retinoic acid (RA) induction was detected using qRT-PCR, Western blotting and immunofluorescence. Neurons of 10-day differentiation were treated with the PRDX1 inhibitor H7, MPP+ and H7 plus MPP+. The cell viability, the amounts of apoptotic nuclei, DHE signals, and the expression of p53, p-Akt and p-mTOR were determined. The colocalization of eEF1A2 and PRDX1 was visualized using confocal microscopy.KEY FINDINGS:eEF1A2 gradually increased after RA-induced differentiation of SH-SY5Y cells, while PRDX1 protein gradually decreased. MPP+ treatment increased eEF1A2 in both undifferentiated and differentiated neurons; however, PRDX1 appeared to elevate only in mature neurons. The inhibition of the PRDX1 activity with H7 promoted MPP+-induced cell death, as evidenced by decreased cell viability, increased apoptotic nuclei, increased the DHE signal, and increased p53. However, H7 induced the activation of the prosurvival Akt and mTOR in MPP+-treated cells. Besides, a colocalization of eEF1A2 and PRDX1 was evidenced in MPP+-treated neurons. This colocalization was possibly prevented by inhibiting the PRDX1 activity, resulting in aggravated neuronal death.SIGNIFICANCE:Our results suggest that the possible association between eEF1A2 and PRDX1 may be a promising target for modifying neuronal death in PD.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the aggregation of α-synuclein protein and selective death of dopaminergic (DA) neurons in the substantia nigra of the midbrain. Although the molecular pathogenesis of PD is not completely understood, a recent study has reported that eukaryotic translation elongation factor 1 alpha (eEF1A) declined in the PD-affected brain. Therefore, the roles of eEF1A1 and eEF1A2 in the prevention of DA neuronal cell death in PD are aimed to be investigated. Herein, by using Caenorhabditis elegans as a PD model, we investigated the role of eft-3/eft-4, the worm homolog of eEF1A1/eEF1A2, on 6-hydroxydopamine (6-OHDA)-induced DA neuron degeneration. Our results demonstrated that the expressions of eft-3 and eft-4 were decreased in the 6-OHDA-induced worms. RNA interference (RNAi) of eft-3 and eft-4 resulted in dramatic exacerbation of DA neurodegeneration induced by 6-OHDA, as well as aggravated the food-sensing behavior, ethanol avoidance, and decreased lifespan when compared with only 6-OHDA-induced worms. Moreover, downregulation of eft-3/4 in 6-OHDA-induced worms suppressed the expression of the anti-apoptotic genes, including PI3K/age-1, PDK-1/pdk-1, mTOR/let-363, and AKT-1,2/akt-1,2, promoting the expression of apoptotic genes such as BH3/egl-1 and Caspase-9/ced-3. Collectively, these findings indicate that eEF1A plays an important role in the 6-OHDA-induced neurodegeneration through the phosphatidylinositol 3-kinase (PI3K)/serine/threonine protein kinase (Akt)/mammalian target of rapamycin (mTOR) pathway and that eEF1A isoforms may be a novel and effective pro-survival factor in protective DA neurons against toxin-induced neuronal death.

Caffeine is a popular psychostimulant, which is frequently consumed with ethanol. However, the effects of caffeine on neuronal cells constantly exposed to ethanol have not been investigated. Apoptosis and oxidative stress occurring in ethanol-induced neurotoxicity were previously associated with decreased phosphorylation of the mTOR/p70S6K/4E-BP1 signaling proteins. Evidence also suggested that caffeine inhibits the mTOR pathway. In this study, human SH-SY5Y neuroblastoma cells were exposed to caffeine after pretreatment for 24 hours with ethanol. Results indicated that both ethanol and caffeine caused neuronal cell death in a dose- and time-dependent manner. Exposure to 20-mM caffeine for 24 hours magnified reduced cell viability and enhanced apoptotic cell death induced by 200 mM of ethanol pretreatment. The phosphorylation of mTOR, p70S6K, and 4E-BP1 markedly decreased in cells exposed to caffeine after ethanol pretreatment, associated with a decrease of the mitochondrial membrane potential (ΔΨm). These findings suggested that caffeine treatment after neuronal cells were exposed to ethanol resulted in marked cell damages, mediated through enhanced inhibition of mTOR/p70S6K/4E-BP1 signaling leading to impaired ΔΨm and, eventually, apoptotic cell death.