Promising 8-Aminoquinoline-Based Metal Complexes in the Modulation of SIRT1/3-FOXO3a Axis against Oxidative Damage-Induced Preclinical Neurons

The discovery of novel bioactive molecules as potential multifunctional neuroprotective agents has clinically drawn continual interest due to devastating oxidative damage in the pathogenesis and progression of neurodegenerative diseases. Synthetic 8-aminoquinoline antimalarial drug is an attractive pharmacophore in drug development and chemical modification owing to its wide range of biological activities, yet the underlying molecular mechanisms are not fully elucidated in preclinical models for oxidative damage. Herein, the neuroprotective effects of two 8-aminoquinoline-uracil copper complexes were investigated on the hydrogen peroxide-induced human neuroblastoma SH-SY5Y cells. Both metal complexes markedly restored cell survival, alleviated apoptotic cascades, maintained antioxidant defense, and prevented mitochondrial function by upregulating the sirtuin 1 (SIRT1)/3-FOXO3a signaling pathway. Intriguingly, in silico molecular docking and pharmacokinetic prediction suggested that these synthetic compounds acted as SIRT1 activators with potential drug-like properties, wherein the uracil ligands (5-iodoracil and 5-nitrouracil) were essential for effective binding interactions with the target protein SIRT1. Taken together, the synthetic 8-aminoquinoline-based metal complexes are promising brain-targeting drugs for attenuating neurodegenerative diseases.

Proteomic Analysis Reveals the Neurotoxic Effects of Chronic Methamphetamine Self-Administration-Induced Cognitive Impairments and the Role of Melatonin-Enhanced Restorative Process during Methamphetamine Withdrawal

Cognitive flexibility is a crucial ability in humans that can be affected by chronic methamphetamine (METH) addiction. The present study aimed to elucidate the mechanisms underlying cognitive impairment in mice chronically administered METH via an oral self-administration method. Further, the effect of melatonin treatment on recovery of METH-induced cognitive impairment was also investigated. Cognitive performance of the mice was assessed using an attentional set shift task (ASST), and possible underlying neurotoxic mechanisms were investigated by proteomic and western blot analysis of the prefrontal cortex (PFC). The results showed that mice-administered METH for 21 consecutive days exhibited poor cognitive performance compared to controls. Cognitive deficit in mice partly recovered after METH withdrawal. In addition, mice treated with melatonin during METH withdrawal showed a higher cognitive recovery than vehicle-treated METH withdrawal mice. Proteomic and western blot analysis revealed that METH self-administration increased neurotoxic markers, including disruption to the regulation of mitochondrial function, mitophagy, and decreased synaptic plasticity. Treatment with melatonin during withdrawal restored METH-induced mitochondria and synaptic impairments. These findings suggest that METH-induced neurotoxicity partly depends on mitochondrial dysfunction leading to autophagy-dependent cell death and that the recovery of neurological impairments may be enhanced by melatonin treatment during the withdrawal period.

Cognitive impairment and changes of red blood cell components and serum levels of IL-6, IL-18, and L-tryptophan in methamphetamine abusers

The deficit in cognitive function is more concerning in methamphetamine (MA) users. The cognitive deficit was suspected to be the consequence of neuroinflammation-induced neurological dysregulation. In addition, activating the key enzyme in the tryptophan metabolic pathway by pro-inflammatory cytokines results in metabolite toxicity, further generating cognitive impairments. However, the evidence for the role of neuroinflammation and tryptophan metabolites involved in MA-induced cognitive deficit needs more conclusive study.

OBJECTIVES

This retrospective study aimed to determine blood-inflammatory markers, tryptophan metabolite-related molecules, and cognitive function in MA abusers compared to healthy control (HC) participants.

METHODS

The cognitive functions were evaluated using Stroop, Go/No-Go, One Back Task (OBT), and Wisconsin Card Sorting Test-64 (WCST-64). Blood samples were analyzed for complete blood count (CBC) analysis, serum inflammatory cytokines interleukin (IL)-6 and IL-18 and tryptophan metabolites.

RESULTS

MA group exhibited poor cognitive performance in selective attention, inhibition, working memory, cognitive flexibility, concept formation and processing speed compared to HC. Reduction in red blood cell (RBC) components but induction in white blood cells (WBCs) and IL-6 were observed in MA abusers, which might indicate anemia of (systemic chronic low-grade) inflammation. In addition, the depletion of precursor in the tryptophan metabolic pathway, L-tryptophan was also observed in MA users, which might represent induction in tryptophan metabolites.

CONCLUSION

These findings emphasize that blood biomarkers might be a surrogate marker to predict the role of neuroinflammation and abnormal tryptophan metabolite in MA-induced cognitive impairments.

Neuroprotective Properties of Bis-Sulfonamide Derivatives Against 6-OHDA-Induced Parkinson's Model via Sirtuin 1 Activity and in silico Pharmacokinetic Properties

Parkinson's disease (PD) is considered one of the health problems in the aging society. Due to the limitations of currently available drugs in preventing disease progression, the discovery of novel neuroprotective agents has been challenged. Sulfonamide and its derivatives were reported for several biological activities. Herein, a series of 17 bis-sulfonamide derivatives were initially tested for their neuroprotective potential and cytotoxicity against the 6-hydroxydopamine (6-OHDA)-induced neuronal death in SH-SY5Y cells. Subsequently, six compounds (i.e., 2, 4, 11, 14, 15, and 17) were selected for investigations on underlying mechanisms. The data demonstrated that the pretreatment of selected compounds (5 μM) can significantly restore the level of cell viability, protect against mitochondrial membrane dysfunction, decrease the activity of lactate dehydrogenase (LDH), decrease the intracellular oxidative stress, and enhance the activity of NAD-dependent deacetylase sirtuin-1 (SIRT1). Molecular docking was also performed to support that these compounds could act as SIRT1 activators. In addition, in silico pharmacokinetic and toxicity profile prediction was also conducted for guiding the potential development. Thus, the six neuroprotective bis-sulfonamides were highlighted as potential agents to be further developed for PD management.

Impact of a Holistic Health Intervention on the Well-Being of Elderly Thais

OBJECTIVE: Mental stress is a major risk factor of metabolic diseases and impairs quality of life in the elderly. The goal of this study was to investigate whether a mindfulness-based intervention can improve health parameters and reduce stress-related hormones in elderly Thais. METHODS: A total of 192 participants were recruited from urban (n = 96) and rural areas (n = 96) in central region of Thailand. Creative visual art relaxation and meditative movement exemplified by Dao De Xin Xi exercise were introduced as monthly workshops and individual participants were encouraged to practice regularly for three months. General health status, levels of blood pressure (BP), fasting blood sugar (FBS), cortisol and dehydroepiandrosteone (DHEA) were evaluated before and after completing the intervention. RESULTS: This mindfulness-based intervention was effective as assessed by several biological health parameters. However, the degree of effectiveness differed between participants in urban and rural groups. In urban group, BPs were significantly reduced in hypertension and pre-hypertension subgroups of participants, and levels of DHEA in low DHEA participants were significantly increased after the intervention. In contrast, FBS levels in diabetic and pre-diabetic participants in the rural group, but not in the urban group, were significantly decreased after the intervention. We found a trend toward improvement of cortisol levels in both groups. However, the levels of glycated hemoglobin in either group remained unchanged. CONCLUSION: This mindfulness-based intervention to elderly people improved health parameters related to metabolic diseases. Therefore, applying the intervention in primary healthcare may help promote the well-being in elderly.

Modulatory Effects of Alpha-Mangostin Mediated by SIRT1/3-FOXO3a Pathway in Oxidative Stress-Induced Neuronal Cells

Background

alpha-Mangostin, a polyphenolic xanthone, is primarily found in the pericarp of mangosteen throughout Southeast Asia and is considered as the “Queen of Fruit” in Thailand. Nonetheless, it is not clarified how alpha-mangostin protects neuronal cells against oxidative stress.

Objective

In this study, molecular mechanisms underlying the neuroprotective effect of alpha-mangostin in defending hydrogen peroxide (H2O2)-induced neurotoxicity was explored.

Methods

cytotoxicity, reactive oxygen species (ROS) generation, apoptotic cascades, and protein expression profiles were performed incorporation of molecular docking.

Results

Human SH-SY5Y cells were pretreated with 1 μM alpha-mangostin for 3 h prior to exposure to 400 μM H2O2. alpha-Mangostin significantly inhibited oxidative stress-induced cell death in neuronal cells by reducing BAX protein, decreasing caspase-3/7 activation, and increasing anti-apoptotic BCL-2 protein. Collectively, alpha-mangostin was demonstrated to be a prominent ROS suppressor which reversed the reduction of antioxidant enzymes (CAT and SOD2). Surprisingly, alpha-mangostin significantly promoted the expression of the sirtuin family and the FOXO3a transcription factor exerting beneficial effects on cell survival and longevity. A molecular docking study predicted that alpha-mangostin is directly bound to the active site of SIRT1.

Conclusion

Findings from this study suggest that alpha-mangostin potentially serves as a promising therapeutic compound against oxidative stress by activation of the SIRT1/3-FOXO3a pathway comparable to the effect of memantine, an anti-AD drug used for the treatment of moderate to severe dementia.

Protective Efficacy of Spilanthes acmella Murr. Extracts and Bioactive Constituents in Neuronal Cell Death

Spilanthes acmella Murr., a well-known Thai traditional medicine, has been used for treatment of toothache, rheumatism and fever. Diverse pharmacological activities of S. acmella Murr. have been reported. In the present study antioxidative and neuroprotective effects of S. acmella Murr. extracts as well as bioactive scopoletin, vanillic acid and trans-ferulic acid found in the aerial parts of this plant species have been described. Protective effect of S. acmella Murr. extracts and bioactive compounds on dexamethasone induced neuronal cells death was investigated. Different plant crude ethyl acetate (EtOAc) and methanol (MeOH) extracts including pure compounds of S. acmella Murr. were evaluated in human neuroblastoma SH-SY5Y cells. Cytotoxic effects were performed by MTT assay. Mechanisms involved in the antioxidant effects of S. acmella Murr. regarding the activation of antioxidant marker proteins such as SOD2 and SIRT3 were determined using DCFH-DA assay, western blot analysis and immunocytochemistry. Dexamethasone significantly caused the decrease of SH-SY5Y cell viability. Conversely, the increases in reactive oxygen species (ROS), autophagy and apoptosis were observed in dexamethasone-treated cells. S. acmella Murr. MeOH and EtOAc extracts, as well as the bioactive compounds reversed the toxic effect of dexamethasone by increasing the cell viability, SIRT3 protein expression but reducing the ROS, autophagy and apoptosis. This study demonstrated that S. acmella Murr. may exert its protective effects against ROS through SOD2 and SIRT3 signaling pathways in dexamethasone-induced neurotoxicity. S. acmella Murr. may be a candidate therapy for neuroprotection.

Spilanthes acmella Murr. ameliorates chronic stress through improving mitochondrial function in chronic restraint stress rats

Chronic stress is a risk factor for the development of psychiatric illnesses through impairment of the ability to appropriately regulate physiological and behavioral responses, but the molecular events that lead to damage of hippocampal neurons remain unclear. The medicinal herb Spilanthes acmella Murr. has been used as a traditional medicine for various diseases and its extracts exhibit antioxidant activity. The present study explored the molecular signals of mitochondrial dynamics and investigated the beneficial effects of S. acmella Murr. An ethyl acetate extract of this plant was used to assess mitochondrial dynamics in response to chronic restraint stress (CRS) in male Sprague-Dawley rats. The results demonstrated that the S. acmella Murr. extract reduced the expression of mitochondrial fission protein but induced HSP60, MnSOD and ATPsynthase in the hippocampus of the CRS rats. In addition, S. acmella Murr. extract reversed depressive symptoms in the forced swim test. Our findings suggested that S. acmella Murr. extract provides a potential treatment of chronic stress, and that the mechanism is associated with the alleviation of neuronal injury and maintenance of mitochondrial function.

Mechanisms and Neuroprotective Activities of Stigmasterol Against Oxidative Stress-Induced Neuronal Cell Death via Sirtuin Family

Background: Accumulating studies have confirmed that oxidative stress leads to the death of neuronal cells and is associated with the progression of neurodegenerative diseases, including Alzheimer's disease (AD). Despite the compelling evidence, there is a drawback to the use of the antioxidant approach for AD treatment, partly due to limited blood-brain barrier (BBB) permeability. Phytosterol is known to exhibit BBB penetration and exerts various bioactivities such as antioxidant and anticancer effects, and displays a potential treatment for dyslipidemia, cardiovascular disease, and dementia. Objective: In this study, the protective effects of stigmasterol, a phytosterol compound, on cell death induced by hydrogen peroxide (H2O2) were examined in vitro using human neuronal cells (SH-SY5Y cells). Methods: MTT assay, reactive oxygen species measurement, mitochondrial membrane potential assay, apoptotic cell measurement, and protein expression profiles were performed to determine the neuroprotective properties of stigmasterol. Results: H2O2 exposure significantly increased the levels of reactive oxygen species (ROS) within the cells thereby inducing apoptosis. On the contrary, pretreatment with stigmasterol maintained ROS levels inside the cells and prevented oxidative stress-induced cell death. It was found that pre-incubation with stigmasterol also facilitated the upregulation of forkhead box O (FoxO) 3a, catalase, and anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) in the neurons. In addition, the expression levels of sirtuin 1 (SIRT1) were also increased while acetylated lysine levels were decreased, indicating that SIRT1 activity was stimulated by stigmasterol, and the result was comparable with the known SIRT1 activator, resveratrol. Conclusion: Taken together, these results suggest that stigmasterol could be potentially useful to alleviate neurodegeneration induced by oxidative stress.

Sesamin and sesamol attenuate H2O2-induced oxidative stress on human neuronal cells via the SIRT1-SIRT3-FOXO3a signaling pathway

Background: An imbalance of free radicals and antioxidant defense systems in physiological processes can result in protein/DNA damage, inflammation, and cellular apoptosis leading to neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). Sesamin and sesamol, compounds derived from sesame seeds and oil, have been reported to exert various pharmacological effects, especially antioxidant activity. However, their molecular mechanisms against the oxidative stress induced by exogenous hydrogen peroxide (H₂O₂) remain to be elucidated. Aim: In this study, neuroprotective effects of sesamin and sesamol on H₂O₂-induced human neuroblastoma (SH-SY5Y) cell death and possible signaling pathways in the cells were explored. Methods: MTT assay and flow cytometry were conducted to determine cell viability and apoptotic profiles of neuronal cells treated with sesamin and sesamol. Carboxy-DCFDA assay was used to measure reactive oxygen species (ROS). Moreover, Western blot analysis was performed to investigate protein profiles associated with neuroprotection. Results: Pretreatment of the cells with 1 µM of sesamin and sesamol remarkably reduced the SH-SY5Y cell death induced by 400 µM H₂O₂ as well as the intracellular ROS production. Moreover, the molecular mechanisms underlying neuroprotection of the compounds were associated with activating SIRT1-SIRT3-FOXO3a expression, inhibiting BAX (proapoptotic protein), and upregulating BCL-2 (anti-apoptotic protein). Conclusion: The findings suggest that sesamin and sesamol are compounds that potentially protect neuronal cells against oxidative stress similar to that of the resveratrol, the reference compound. These antioxidants are thus of interest for further investigation in in vivo models of neuroprotection.

Melatonin prevents calcineurin-activated the nuclear translocation of nuclear factor of activated T-cells in human neuroblastoma SH-SY5Y cells undergoing hydrogen peroxide-induced cell death

The interaction between the activation of protein phosphatase, calcineurin (CaN), and the dephosphorylation and nuclear translocation of nuclear factor of activated T-cells (NFAT), a transcriptional factor in the immune system, has attracted interest as a key factor responsible for the cell death process. In this study, the effects of melatonin on the interaction between CaN and NFAT signaling during oxidative stress-induced cell death were investigated. Human neuroblastoma SH-SY5Y cells were treated with the non-radical reactive oxygen species hydrogen peroxide (H₂O₂). Cells were treated with 200 μM H₂O₂ for the indicated time. Some H₂O₂-treated cells were pretreated with melatonin for 1 h. Control cells were treated with the same concentration of ethanol used to dilute melatonin. H₂O₂-induced cell death promoted increases in reactive oxygen species (ROS) production and the nuclear translocation of NFAT, which were related to increased levels the active, cleaved form of CaN (32.5 kDa). In addition, pretreatment of H₂O₂-treated cells with melatonin decreased cell death, ROS production, the levels of the active-cleaved form of CaN and the nuclear translocation of NFAT. Based on these findings, melatonin may exert its neuroprotective effects on oxidative damage-induced cell death by inhibiting CaN-activated the nuclear translocation of NFAT.

Butein, isoliquiritigenin, and scopoletin attenuate neurodegeneration via antioxidant enzymes and SIRT1/ADAM10 signaling pathway

Neuronal cell death is a key feature of neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. Plant polyphenols, namely butein, isoliquiritigenin, and scopoletin, have been shown to exhibit various biological activities including anti-inflammatory, antimicrobial, and antioxidant activities. Herein, butein, isoliquiritigenin, and scopoletin were explored for their neuroprotective properties against oxidative stress-induced human dopaminergic SH-SY5Y cell death. The cells exposed to hydrogen peroxide (H₂O₂) revealed a reduction in cell viability and increases in apoptosis and levels of reactive oxygen species (ROS). Interestingly, pretreatment of SH-SY5Y cells with 5 μM of butein, isoliquiritigenin, or scopoletin protected against the cell death induced by H₂O₂, and decreased the levels of apoptotic cells and ROS. In addition, the levels of SIRT1, FoxO3a, ADAM10, BCL-2, and antioxidant enzymes (catalase and SOD2) were maintained in the cells pretreated with butein, isoliquiritigenin, or scopoletin before H₂O₂ treatment compared to cells without pretreatment and the reference (resveratrol). Molecular docking analysis revealed that the interactions between the activator-binding sites of SIRT1 and the phenolic compounds were similar to those of resveratrol. Taken together, the data suggest that these polyphenolic compounds could be potential candidates for prevention and/or treatment of neurodegeneration.

Neuronal cells exposed to H₂O₂ may undergo increase ROS, reduction in cell viability and cell death. Butein, isoliquiritigenin, and scopoletin ameliorated H₂O₂-induced neurotoxicity by reducing ROS, balancing antioxidants and activating SIRT1-FoxO3a-ADAM10 pathway.

Mitochondrial Dynamics Impairment in Dexamethasone-Treated Neuronal Cells

Dexamethasone is an approved steroid for clinical use to activate or suppress cytokines, chemokines, inflammatory enzymes and adhesion molecules. It enters the brain, by-passing the blood brain barrier, and acts through genomic mechanisms. High levels of dexamethasone are able to induce neuronal cell loss, reduce neurogenesis and cause neuronal dysfunction. The exact mechanisms of steroid, especially the dexamethasone contribute to neuronal damage remain unclear. Therefore, the present study explored the mitochondrial dynamics underlying dexamethasone-induced toxicity of human neuroblastoma SH-SY5Y cells. Neuronal cells treatment with the dexamethasone resulted in a marked decrease in cell proliferation. Dexamethasone-induced neurotoxicity also caused upregulation of mitochondrial fusion and cleaved caspase-3 proteins expression. Mitochondria fusion was found in large proportions of dexamethasone-treated cells. These results suggest that dexamethasone-induced hyperfused mitochondrial structures are associated with a caspase-dependent death process in dexamethasone-induced neurotoxicity. These findings point to the high dosage of dexamethasone as being neurotoxic through impairment of mitochondrial dynamics.

Multidisciplinary approaches for targeting the secretase protein family as a therapeutic route for Alzheimer's disease

The continual increase of the aging population worldwide renders Alzheimer's disease (AD) a global prime concern. Several attempts have been focused on understanding the intricate complexity of the disease's development along with the on- andgoing search for novel therapeutic strategies. Incapability of existing AD drugs to effectively modulate the pathogenesis or to delay the progression of the disease leads to a shift in the paradigm of AD drug discovery. Efforts aimed at identifying AD drugs have mostly focused on the development of disease-modifying agents in which effects are believed to be long lasting. Of particular note, the secretase enzymes, a group of proteases responsible for the metabolism of the β-amyloid precursor protein (βAPP) and β-amyloid (Aβ) peptides production, have been underlined for their promising therapeutic potential. This review article attempts to comprehensively cover aspects related to the identification and use of drugs targeting the secretase enzymes. Particularly, the roles of secretases in the pathogenesis of AD and their therapeutic modulation are provided herein. Moreover, an overview of the drug development process and the contribution of computational (in silico) approaches for facilitating successful drug discovery are also highlighted along with examples of relevant computational works. Promising chemical scaffolds, inhibitors, and modulators against each class of secretases are also summarized herein. Additionally, multitarget secretase modulators are also taken into consideration in light of the current growing interest in the polypharmacology of complex diseases. Finally, challenging issues and future outlook relevant to the discovery of drugs targeting secretases are also discussed.

Potential effects and molecular mechanisms of melatonin on the dopaminergic neuronal differentiation of human amniotic fluid mesenchymal stem cells

Melatonin, a highly lipophilic molecule secreted by the pineal gland in the brain, plays a role in various biological functions. Previous studies reported that melatonin exerts its effect on mesenchymal stem cell (MSC) survival and differentiation into osteogenic- and adipogenic-lineage. However, the effect of melatonin in neurogenic differentiation in amniotic fluid (AF)-MSCs remains to be explored, thus we investigated the potential role of melatonin on dopaminergic neuron differentiation in AF-MSCs. The results showed that various concentrations of melatonin did not affect cell viability and proliferative effects of AF-MSCs. Increases in the levels of neuronal protein marker (βIII-tubulin) and dopaminergic neuronal markers (tyrosine hydroxylase, TH and NURR1), but decrease in the level of glial fibrillary acidic protein (GFAP), were observed in melatonin-treated AF-MSCs. Melatonin induced alteration in differential expression patterns of mesenchymal stem cell antigens by reducing CD29, CD45, CD73, CD90 and CD105, but no changing CD34 expressing cells. AF-MSCs were sequentially induced in neurobasal medium containing standard inducing cocktails (ST: bFGF, SHH, FGF8, BDNF), 1 μM melatonin, or a combination of ST and melatonin. The levels of TUJ1, TH, MAP2, NURR1 and dopamine transporter (DAT) were significantly increased in all treated groups when compared with control-untreated cells. Pretreated AF-MSCs with non-selective MT1/MT2 receptors antagonist, luzindole and selective MT2 receptor antagonist, 4-P-PDOT diminished melatonin-induced increase in dopaminergic neuronal markers and phosphorylated ERK but did not diminish increase in phosphorylated CaMKII by melatonin. Pretreatment with mitogen-activated protein kinase (MEK) inhibitor, PD98059 and CaMKII inhibitor, KN-93 were able to abolish increase in the levels of dopaminergic markers in melatonin-treated AF-MSCs. These findings suggest that melatonin promotes dopaminergic neuronal differentiation of AF-MSCs possibly via the induction in ERK and CaMKII pathways through melatonin receptor-dependent and -independent mechanisms, respectively.

Development of competitive lateral flow immunoassay coupled with silver enhancement for simple and sensitive salivary cortisol detection

Cortisol is known as a stress biomarker. The measurement of cortisol levels is an early warning indicator for health conditions and diagnosis of stress-related diseases. Herein, a lateral flow immunoassay using a gold nanoparticle label with a silver enhancement system was developed for the simple, sensitive and rapid detection of cortisol. The developed assay was based on a competitive platform of which cortisol-BSA conjugate was immobilized at the test zone to compete with an analyte. The quantitative analysis was performed using gold nanoparticles (AuNPs) as signal labeling. Sequentially, the silver enhancement solution was applied in order to enhance the sensitivity of the assay with the results easily seen by the naked eye. Using this system, the limit of detection (LOD) was found to be 0.5 ng/mL with a 3.6 fold more sensitive detection than without the enhancement system (LOD = 1.8 ng/mL). The salivary cortisol analysis was in the range of 0.5-150 ng/mL (R² = 0.9984), which is in the clinical acceptable range. For the semi-quantitative analysis, the intensity color of the results was analyzed using an image processing program. The proposed method was successfully applied to detect cortisol in saliva. In addition, the results from our method also complied with the ones of those obtained by using the commercial enzyme-linked immunosorbent assay (ELISA). This developed assay offers great promise for a non-invasive screening test of salivary cortisol.

Development of competitive lateral flow immunoassay coupled with silver enhancement for simple and sensitive salivary cortisol detection

Cortisol is known as a stress biomarker. The measurement of cortisol levels is an early warning indicator for health conditions and diagnosis of stress-related diseases. Herein, a lateral flow immunoassay using a gold nanoparticle label with a silver enhancement system was developed for the simple, sensitive and rapid detection of cortisol. The developed assay was based on a competitive platform of which cortisol-BSA conjugate was immobilized at the test zone to compete with an analyte. The quantitative analysis was performed using gold nanoparticles (AuNPs) as signal labeling. Sequentially, the silver enhancement solution was applied in order to enhance the sensitivity of the assay with the results easily seen by the naked eye. Using this system, the limit of detection (LOD) was found to be 0.5 ng/mL with a 3.6 fold more sensitive detection than without the enhancement system (LOD = 1.8 ng/mL). The salivary cortisol analysis was in the range of 0.5-150 ng/mL (R² = 0.9984), which is in the clinical acceptable range. For the semi-quantitative analysis, the intensity color of the results was analyzed using an image processing program. The proposed method was successfully applied to detect cortisol in saliva. In addition, the results from our method also complied with the ones of those obtained by using the commercial enzyme-linked immunosorbent assay (ELISA). This developed assay offers great promise for a non-invasive screening test of salivary cortisol.

Effect of 8-hydroxyquinoline and derivatives on human neuroblastoma SH-SY5Y cells under high glucose

8-Hydroxyquinoline and derivatives exhibit multifunctional properties, including antioxidant, antineurodegenerative, anticancer, anti-inflammatory and antidiabetic activities. In biological systems, elevation of intracellular calcium can cause calpain activation, leading to cell death. Here, the effect of 8-hydroxyquinoline and derivatives (5-chloro-7-iodo-8-hydroxyquinoline or clioquinol and 8-hydroxy-5-nitroquinoline or nitroxoline) on calpain-dependent (calpain-calpastatin) pathways in human neuroblastoma (SH-SY5Y) cells was investigated. 8-Hydroxyquinoline and derivatives ameliorated high glucose toxicity in SH-SY5Y cells. The investigated compounds, particularly clioquinol, attenuated the increased expression of calpain, even under high-glucose conditions. 8-Hydroxyquinoline and derivatives thus adversely affected the promotion of neuronal cell death by high glucose via the calpain-calpastatin signaling pathways. These findings support the beneficial effects of 8-hydroxyquinolines for further therapeutic development.

Melatonin prevents cytosolic calcium overload, mitochondrial damage and cell death due to toxically high doses of dexamethasone-induced oxidative stress in human neuroblastoma SH-SY5Y cells

Stressor exposure activates the hypothalamic-pituitary-adrenal (HPA) axis and causes elevations in the levels of glucocorticoids (GC) from the adrenal glands. Increasing evidence has demonstrated that prolonged exposure to high GC levels can lead to oxidative stress, calcium deregulation, mitochondrial dysfunction and apoptosis in a number of cell types. However, melatonin, via its antioxidant activity, exhibits a neuroprotective effect against oxidative stress-induced cell death. Therefore, in the present study, we explored the protective effect of melatonin in GC-induced toxicity in human neuroblastoma SH-SY5Y cells. Cellular treatment with the toxically high doses of the synthetic GC receptor agonist, dexamethasone (DEX) elicited marked decreases in the levels of glutathione and increases in ROS production, lipid peroxidation and cell death. DEX toxicity also induced increases in the levels of cytosolic calcium and mitochondrial fusion proteins (Mfn1 and Opa1) but decreases in the levels of mitochondrial fission proteins (Fis1 and Drp1). Mitochondrial damage was observed in large proportions of the DEX-treated cells. Pretreatment of the cells with melatonin substantially prevented the DEX-induced toxicity. These results suggest that melatonin might exert protective effects against oxidative stress, cytosolic calcium overload and mitochondrial damage in DEX-induced neurotoxicity.

Quinoline-based clioquinol and nitroxoline exhibit anticancer activity inducing FoxM1 inhibition in cholangiocarcinoma cells

Purpose

Fork head box M1 (FoxM1) is an oncogenic transcription factor frequently elevated in numerous cancers, including cholangiocarcinoma (CCA). A growing body of evidence documents its diverse functions contributing to tumorigenesis and cancer progression. As such, discovery of agents that can target FoxM1 would be valuable for the treatment of CCA. The quinoline-based compounds, namely clioquinol (CQ) and nitroxoline (NQ), represent a new class of anticancer drug. However, their efficacy and underlying mechanisms have not been elucidated in CCA. In this study, anticancer activities and inhibitory effects of CQ and NQ on FoxM1 signaling were explored using CCA cells.

Methods

The effects of CQ and NQ on cell viability and proliferation were evaluated using the colorimetric 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-(4-sulfophenyl)-2H-tetrazolium (MTS assay). Colony formation and cell migration affected by CQ and NQ were investigated using a clonogenic and a wound healing assay, respectively. To demonstrate the agents’ effects on FoxM1 signaling, expression levels of the target genes were quantitatively determined using real-time polymerase chain reaction.

Results

CQ and NQ significantly inhibited cell survival of HuCCT1 and Huh28 in a dose- and a time-dependent fashion. Further investigations using the rapidly proliferating HuCCT1 cells revealed significant suppression of cell proliferation and colony formation induced by low doses of the compounds. Treatment of CQ and NQ repressed expression of cyclin D1 but enhanced expression of p21. Most importantly, upon CQ and NQ treatment, expression of oncogenic FoxM1 was markedly decreased concomitant with downregulation of various FoxM1’s downstream targets including cdc25b, CENP-B, and survivin. In addition, the compounds distinctly impaired HuCCT1 migration as well as inhibited expression of matrix metalloproteinase (MMP)-2 and MMP-9.

Conclusion

Collectively, this study reports for the first time the anticancer effects of CQ and NQ against CCA cells, and highlights new insights into the mechanism of actions of the quinoline-based compounds to disrupt FoxM1 signaling.

Melatonin attenuates dexamethasone toxicity-induced oxidative stress, calpain and caspase activation in human neuroblastoma SH-SY5Y cells

Glucocorticoids (GCs) have a significant role in the adaptive response of the brain to stress. Increasing evidence has demonstrated that an increase of GC levels may induce neuronal cell death via apoptotic pathways. There is a correlation between over-production of reactive oxygen species (ROS) and an elevation in cytosolic calcium that causes a subsequent increase in the calcium-dependent death-process activation in GC-induced toxicity. Consequently, melatonin, via its antioxidant activity, exhibits a neuroprotective effect against apoptosis induced by intracellular calcium overload. Therefore, in the present study, we explored the protective effect of melatonin in GC-induced toxicity in dopaminergic SH-SY5Y cells. Cellular treatment with the synthetic GCs, dexamethasone (DEX), resulted in a marked decrease in cell viability and in the level of the calpain-inhibitor protein, calpastatin. DEX-induced toxicity also caused an increase in ROS production and the activation of the calcium-dependent cysteine protease, calpain, along with an increase in caspase-3 activation. Pretreatment of the cells with melatonin substantially prevented the decrease in cell viability, over-production of ROS and the activation of calpain and caspase-3, and reversed the depletion in calpastatin levels. These results suggest that melatonin may exert its protective effects against the calpain- and caspase-dependent death process in DEX-induced neurotoxicity.

Glucocorticoids reduce intracellular calcium concentration and protects neurons against glutamate toxicity

Glucocorticoids are steroid hormones which act through the glucocorticoid receptor. They regulate a wide variety of biological processes. Two glucocorticoids, the naturally occurring corticosterone and chemically produced dexamethasone, have been used to investigate the effect of glucocorticoids on Ca(2+)-signalling in cortical co-cultures of neurons and astrocytes. Dexamethasone and to a lesser degree corticosterone both induced a decrease in cytosolic Ca(2+) concentration in neurons and astrocytes. The effect of both compounds can be blocked by inhibition of the plasmamembrane ATPase, calmodulin and by application of a glucocorticoid receptor antagonist, while inhibition of NMDA receptors or the endoplasmic reticulum calcium pump had no effect. Glucocorticoid treatment further protects against detrimental calcium signalling and cell death by modulating the delayed calcium deregulation in response to glutamate toxicity. At the concentrations used dexamethasone and corticosterone did not show cell toxicity of their own. Thus, these results indicate that dexamethasone and corticosterone might be used for protection of the cells from calcium overload.

The protective effect of melatonin on methamphetamine-induced calpain-dependent death pathway in human neuroblastoma SH-SY5Y cultured cells

Methamphetamine (METH) is a potent psychostimulant drug that may cause neuronal cell degeneration. The underlying mechanisms of METH-induced neuronal toxicity remains poorly understood. In this study, we investigated an important role of calpain-dependent cascades in methamphetamine-induced toxicity in human dopaminergic neuroblastoma SH-SY5Y cultured cell lines. In addition, the protective effect of melatonin against METH-induced calpain-dependent death pathway was also investigated. The results of this study show that METH significantly decreased cell viability and tyrosine hydroxylase phosphorylation in SH-SY5Y cultured cells. Melatonin reversed the toxic effect of METH by inducing cell viability. In addition, melatonin was able to restore the reduction in mitochondrial function and phosphorylation of tyrosine hydroxylase in SH-SY5Y treated cells. An induction of calpain expression and activity but a reduction of calpain inhibitor (calpastatin) protein levels were observed in SH-SY5Y cells treated with METH but these effects were diminished by melatonin. These results implicated calpain-dependent death pathways in the processes of METH-induced toxicity and also indicated that melatonin has the capacity to reverse this toxic effect in SH-SY5Y cultured cells.