Neurotoxicity Research最新文献

Ketamine is an anesthetic drug that has been illegally used due to its hallucinogenic effects. Its use is often concomitant with drugs such as ethanol, which can cause irreversible damage to the central nervous system. This study investigates the neurotoxicity of ketamine-ethanol combination in human neuroblastoma SH-SY5Y cell line, exploring the mechanisms preceding cell death. Cell viability, oxidative stress parameters, and apoptosis pathways were assessed after 3 and 6 h of drug exposure. A concentration-response curve using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay determined the lowest observed adverse effect levels for ketamine (1 mM; K1) and ethanol (100 mM; E100). After 12, 24 and 48 h, MTT assay revealed a decrease in cell viability, with a possible synergistic effect in K1E100 at 48 h, confirmed by annexin-V/7-aminoactinomycin D flow cytometry analysis, which showed a higher proportion of late apoptotic cells. Mechanisms preceding cell death were assessed by measuring reduced glutathione (GSH) levels, glutathione-related enzymes activities, and apoptosis markers (caspase-8, Bax, Bcl-2, and caspase-3). GSH levels decreased after 6 h in E100 and K1E100. Glutathione peroxidase activity increased for all groups after 3 h and in K1 and K1E100 after 6 h. Glutathione reductase and glutathione S-transferase activities increased only for K1E100 after 3 h. K1E100 also showed increased caspase-8 and Bax expression after 3 and 6 h, respectively, indicating activation of both extrinsic and intrinsic apoptotic pathways. These results suggest that ketamine-ethanol combination induces neurotoxicity by triggering oxidative stress and apoptosis in a time-dependent manner prior to cell death, increasing the risk for neuronal damage compared to individual drug exposure. While these findings are promising, they should be interpreted with caution due to certain limitations, such as variability in enzyme activity measurements, reduced sample size for some markers, and the use of an immortalized, proliferative cell line. Further studies using differentiated neuronal cells are needed to validate and expand these observations.

Memory decline is a common hallmark signal of neurodegenerative diseases marked by elevated neuroinflammatory cytokines, oxidative damage and cholinergic insufficiency in cortical regions. Studies indicate that inhibiting these cytokines and associated markers may enhance memory and provide neuroprotection. This study investigates the effects of sabinene, a neuroprotective monoterpene found in essential oils with neuroprotective and antioxidant properties, on lipopolysaccharide (LPS)-induced neuroinflammation, oxidative stress and learning/memory impairment in mice. In this study, mice in groups 1 and 2 received normal saline, while groups 3-5 were pretreated with sabinene (5, 10, and 20 mg/kg). Group 6 received donepezil (1 mg/kg) orally. Groups 2-6 were additionally injected with LPS (0.5 mg/kg, i.p.) 30 min post-treatment for 7 days. Behavioral consequences indicating spatial and non-spatial deficits were assessed through Y-maze and novel-object recognition tests, along with locomotor functions conducted. Biochemical markers of neuroinflammation (TNF-α, IL-6), oxidative stress (glutathione, peroxidase, malondialdehyde, nitrite), cholinergic function, and molybdenum enzymes were analyzed in the prefrontal-cortex (PFC) and hippocampus. Sabinene treatment mitigated LPS-induced memory impairments and reduced motor activity. It also significantly decreased acetylcholinesterase activity and malondialdehyde levels in the hippocampus and PFC while increasing glutathione and glutathione peroxidase levels, respectively. Moreover, sabinene reduced LPS-induced molybdenum enzyme elevation in the PFC. Compared to LPS, sabinene significantly lowered TNF-α and IL-6 levels in the PFC and hippocampus while protecting neuronal cell damage in the PFC. Overall, sabinene enhances memory function in LPS-treated mice by reducing oxidative stress and neuroinflammation while improving cholinergic activity and molybdenum enzymes in the cortical regions of mice brains.

Ferroptosis is an iron-dependent and membrane lipid peroxidation-mediated form of programmed or regulated cell death. A number of recent studies have demonstrated that ferroptosis contributes to Alzheimer's disease (AD)-mediated nerve cell death. Melatonin demonstrates strong antioxidant properties and offers protective benefits for the brain in the context of AD. However, it is not fully known whether melatonin protects against ferroptosis and whether ferroptosis affects amyloid precursor protein (APP) processing. In this study, we studied the effects of melatonin on SH-SY5Y cells-induced ferroptosis using erastin, and ferrostatin-1 was used as a ferroptosis inhibitor. To confirm the occurrence of ferroptosis, we conducted measurements of cell cytotoxicity, intracellular iron, reactive oxygen species (ROS), and 4-hydroxynonenal (4-HNE). The protein expressions that were regulated by either ferroptosis or APP processing were measured. Our results revealed that erastin increased intracellular iron levels, ROS, and 4-HNE lipid peroxidation in SH-SY5Y cells, resulting in an increased percentage of cell death. Erastin disrupted the regulation of proteins involved in ferroptosis and increased the production of amyloid beta (Aβ) through APP proteolysis. Following melatonin treatment, intracellular iron, ROS, and 4-HNE levels were significantly reduced. Additionally, the cystine/glutamate antiporter (system xc^-) and glutathione peroxidase 4 (GPX4) were increased, and acyl-CoA synthetase long chain family member 4 (ACSL4) was diminished. APP, β-site-APP cleaving enzyme 1 (BACE1), presenilin 1 (PS1) and Aβ production were alleviated in erastin-treated SH-SY5Y cells. In conclusion, melatonin effectively inhibits ferroptosis-related cell death and AD-like conditions induced by erastin in SH-SY5Y human neuroblastoma cell lines.

Membrane composition, permeability and fluidity are essential for proper cellular function. According to the membrane aging hypothesis, aging-related diseases, including neurodegenerative disorders, arise from the aging of cell membranes. Membrane proteins, such as the insulin receptor, rely on an optimal membrane environment for proper partitioning and functionality. Our goal was to investigate the effects of streptozotocin (STZ) and L-buthionine-sulfoximine (BSO), two commonly used agents to model aging and neurodegeneration, on membrane composition and permeability, as well as their impact on insulin signaling. Mouse neuroblastoma 2a cell line (neuro-2a) were treated with STZ (6 h) and BSO (24 h). Cell viability was assessed by the MTT assay. Cholesterol and sphingomyelin content were quantified by commercial kits, while membrane polarity was evaluated with the Laurdan probe. Gene expression of Srebf2 and Cyp46a1 was analyzed by qPCR. Proteins from the insulin signaling pathway were examined by immunoblotting. STZ treatment reduced neuronal cholesterol content, downregulated Srebf2 and Cyp46a1 gene expression, and decreased membrane packing. In contrast, BSO-treated cells exhibited increased sphingomyelin content, upregulated Srebf2 and Cyp46a1 gene expression, and decreased membrane packing. Both treatments induced an insulin-resistant state, which we attribute to alterations in the membrane environment.

This study investigates the potential protective role of annexin A1 (ANXA1) in cell models of H₂O₂-induced Alzheimer's disease. PC12 cells exposed to varying concentrations of H₂O₂ exhibited a dose-dependent decrease in cell viability. H₂O₂ exposure led to elevated reactive oxygen species (ROS) levels, reduced superoxide dismutase (SOD) and catalase (CAT) activities, and a decline in ANXA1 protein expression. Under oxidative stress, ANXA1 overexpression increased cell viability, reduced apoptosis rate, enhanced the expression of microtubule-associated protein 3 (LC3) II/I while reducing phosphorylated calcium/calmodulin-dependent protein kinase II (p-CAMK2)/CAMK2 and phosphorylated beclin 1 (p-BECN1)/BECN1. Conversely, ANXA1 knockdown produced contrasting effects. Overexpression of ANXA1, accompanied by administration of KN-93 (a competitive inhibitor of CAMK2), can synergistically diminished p-CAMK2/CAMK2 and p-BECN1/BECN1 levels while significantly increasing LC3 II/I levels, autophagosomes, and autolysosomes. In conclusion, ANXA1 demonstrated a protective role in H₂O₂-induced oxidative stress damage model in PC12 cells by inhibiting the CAMK2/BECN1 signaling pathway and enhancing autophagy.

Increasing evidence of ocular impairments in Alzheimer's disease (AD) has drawn the attention of researchers worldwide towards retinal neurodegeneration in AD. The AD-associated changes observed in the retina include visual discrepancies, pupil size modulations, retinal nerve layer changes, retinal blood flow alterations and histopathological changes. The brain cells that act as pathological triggers for the progression of retinal neurodegeneration associated with AD are microglia, astrocytes and neurons. Various molecular pathways lead to structural and functional abnormalities in the retina, significantly affecting the brain including Aβ accumulation, apoptosis, inflammation and oxidative stress. Therapeutic agents under development that ameliorate disease conditions by targeting retinal anomalies include mesenchymal stem cell-conditioned media, BDNF, glatiramer acetate, salvianolic acid B, Lycium barbarum extract and exosomes. Investigating real-time alterations in the retina in AD may not only affect diagnostic approaches but also help to clarify neuropathological pathways and offer helpful measurements for assessing novel therapeutic approaches for AD.

Methamphetamine (METH) abuse and HIV infection are major public health concerns worldwide. While both METH and HIV- 1 Tat proteins can induce neurotoxicity and synergistic effects on the nervous system, the mechanisms by which they act synergistically remain unclear. Our recent research shows that neuroinflammation plays an important role in neurotoxicity induced by METH and HIV- 1 Tat proteins, but the regulatory mechanism has not been clarified. Tripartite Motif Containing 13 (TRIM13) is a protein known to regulate the inflammatory response through ubiquitination of Tumor Necrosis Factor Receptor Associated Factor 6 (TRAF6). This study investigated the role of TRIM13 and TRAF6 in the inflammatory response of U- 87 MG cells induced by METH and HIV- 1 Tat proteins. U- 87 MG cells were treated with 2 mM METH and/or 100 nM HIV- 1 Tat protein. Western blot (WB), immunofluorescence (IF), and co-immunoprecipitation (Co-IP) experiments were employed to elucidate the role of TRIM13 and TRAF6. The results demonstrated that METH and HIV- 1 Tat protein could synergistically induce an inflammatory response in U- 87 MG cells. Furthermore, the knockdown of TRIM13 significantly enhanced this inflammatory response, while the inhibition of TRAF6 significantly weakened it. Additionally, the study revealed that TRIM13 could degrade TRAF6 via ubiquitination. In conclusion, this study suggests that TRIM13 regulates TRAF6 ubiquitination to dampen the inflammatory response of U- 87 MG cells induced by METH and HIV- 1 Tat proteins. These findings highlight TRIM13 and TRAF6 as potential targets for therapeutic intervention in the context of METH and HIV- 1 Tat protein-induced inflammatory responses and neurotoxic effects.

Recent studies have identified the angiotensin-converting enzyme (ACE) gene as a potential candidate influencing Alzheimer's disease (AD) risk. It is crucial to investigate the impact of ACE on AD pathology and its underlying mechanisms. A total of 450 non-demented participants from the Alzheimer's disease Neuroimaging Initiative (ADNI) with data on cerebrospinal fluid (CSF) ACE, AD core biomarkers and inflammation-related biomarkers were included. Multiple linear regression was used to assess the associations among CSF ACE, AD core biomarkers and inflammation-related biomarkers. And we used the mediation models to investigate the potential mechanisms through which ACE influenced AD pathology. The results of multiple linear regression were shown that CSF ACE was significantly correlated with CSF Aβ₄₂, P-tau, T-tau (all P < 0.001), and inflammation-related biomarkers (soluble triggering receptor expressed on myeloid cells 2 [sTREM2], progranulin [PGRN], glial fibrillary acidic protein [GFAP], transforming growth factor [TGF]-β1, TGF-β2, TGF-β3, tumor necrosis factor [TNF]-R1, TNF-R2, TNF-α, interleukin [IL]-21, IL-6, IL-7, IL-9, IL-10, IL-12p40, vascular cell adhesion molecule-1 [VCAM-1], and intercellular adhesion molecule-1 [ICAM-1]) (all P < 0.05). In addition, the mediation analysis results showed that the association of CSF ACE and inflammation-related biomarkers (sTREM2, PGRN, TGF-β1, TGF-β2, TNFR1, IL-6, IL-7, IL-9, and VCAM-1) mediated the correlation of CSF Aβ₄₂ with P-tau. Our findings show that CSF ACE and neuroinflammation are correlated and that their correlation mediates the link between Aβ pathology and P-tau. This suggests ACE may play a significant role in the progression from Aβ pathology to tau pathology.

HIV-associated neurocognitive disorder (HAND) persists in people living with HIV (PLWH) despite antiretroviral therapy. HAND is characterized by synapto-dendritic damage, yet the cause of this pathology is still under investigation. Various viral proteins, including the envelope protein gp120, have been proposed to be the leading neurotoxic agents underlying HIV-mediated neuronal degeneration. Gp120 has been shown to bind to neuronal microtubules (MTs) and impair their functions. The dynamic properties of MTs are modulated by microtubule-associated proteins (MAP), including MAP2, which is particularly abundant in dendrites. This review article explores how gp120 could be altering the function of the neuronal cytoskeleton by affecting MAP2. These effects may serve as a causal link between viral proteins and HAND pathology.