Effect of Acrylamide and Mycotoxins in SH-SY5Y Cells: A Review

Thermal processes induce the formation of undesired toxic components, such as acrylamide (AA), which has been shown to induce brain toxicity in humans and classified as Group 2A by the International Agency of Research in Cancer (IARC), as well as some mycotoxins. AA and mycotoxins' toxicity is studied in several in vitro models, including the neuroblastoma cell line model SH-SY5Y cells. Both AA and mycotoxins occur together in the same food matrix cereal base (bread, pasta, potatoes, coffee roasting, etc.). Therefore, the goal of this review is to deepen the knowledge about the neurological effects that AA and mycotoxins can induce on the in vitro model SH-SY5Y and its mechanism of action (MoA) focusing on the experimental assays reported in publications of the last 10 years. The analysis of the latest publications shows that most of them are focused on cytotoxicity, apoptosis, and alteration in protein expression, while others are interested in oxidative stress, axonopathy, and the disruption of neurite outgrowth. While both AA and mycotoxins have been studied in SH-SY5Y cells separately, the mixture of them is starting to draw the interest of the scientific community. This highlights a new and interesting field to explore due to the findings reported in several publications that can be compared and the implications in human health that both could cause. In relation to the assays used, the most employed were the MTT, axonopathy, and qPCR assays. The concentration dose range studied was 0.1-10 mM for AA and 2 fM to 200 µM depending on the toxicity and time of exposure for mycotoxins. A healthy and varied diet allows the incorporation of a large family of bioactive compounds that can mitigate the toxic effects associated with contaminants present in food. Although this has been reported in some publications for mycotoxins, there is still a big gap for AA which evidences that more investigations are needed to better explore the risks for human health when exposed to AA and mycotoxins.

Individual and combined effect of acrylamide, fumitremorgin C and penitrem A on human neuroblastoma SH-SY5Y cells

Acrylamide (AA) is a chemical compound that can be formed in certain foods during high-temperature cooking processes such as frying, baking, and roasting. Exposure to AA has been linked to several neurological effects, including peripheral neuropathy, ataxia, and impaired cognitive function. Penitrem A (PEN A) and Fumitremorgin C (FTC) are toxic mycotoxins produced by certain species of fungi, such as Penicillium Crustosum, Aspergillus Fumigatus and Neosartorya Fischeri. Both mycotoxins are commonly found in contaminated foods and animal feeds and have been linked to several adverse health effects in humans and animals, including the ability to disrupt normal functioning of the nervous system, tremors, seizures, muscle spasms, and convulsions. AA, PEN A, and FTC are all chemical contaminants. Understanding their toxicity and how they may affect human cells can help food safety authorities to establish safe exposure levels for these compounds through food and develop strategies to reduce their presence. The aim of this study was to explore the combined in vitro toxicological effects of AA, PEN A and FTC in SH-SY5Y cells. For this purpose, cells were treated with AA, FTC, and PEN A as an individual and combined treatment. The types of interactions were assessed by the isobologram analysis. The cell cycle was performed by flow cytometry. Additive effect in binary and tertiary combinations was the major effect according to isobologram graphics. Our results demonstrate that PEN A possessed the highest potential in disturbing cell cycle progression by disrupting cell density in G0/G1 phase.

Effects of acrylamide on protein degradation pathways in human liver-derived cells and the efficacy of N-acetylcysteine and curcumin

Acrylamide is a harmful chemical, and its metabolism occurs mainly in the liver. Acrylamide can form adducts on proteins. Protein homeostasis is vital for metabolic and secretory functions of the liver. No study has investigated the effect of acrylamide on the ubiquitin-proteasome system (UPS). Also, the effect of acrylamide on autophagy and its regulation is not fully known. We aimed to investigate the effects of acrylamide on the UPS, autophagy, mammalian target of rapamycin (mTOR), and heat shock protein 70 (HSP70) in HepG2 cells as well as to examine the effects of N-acetylcysteine and curcumin on these parameters in acrylamide-treated cells. HepG2 cells were initially treated with variable concentrations of acrylamide (0.01-0.1-1-10 mM) for 24 hours. Then, HepG2 cells were treated with 5 mM N-acetylcysteine and 6.79 µM curcumin in the presence of 10 mM acrylamide for 24 hours. Cell viability was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Ubiquitinated protein, mTOR, microtubule-associated proteins 1 A/1B light chain 3B-II (LC3B-II), and HSP70 levels were measured by immunoblotting. Acrylamide at 10 mM concentration, without any significant change at lower concentrations, caused an increase in ubiquitinated protein, LC3B-II, and HSP70 levels and a decrease in mTOR phosphorylation. Furthermore, 5 mM N-acetylcysteine caused a decrease in ubiquitinated protein and HSP70 levels; however, 6.79 µM curcumin did not affect 10 mM in acrylamide-treated cells. Our study showed that acrylamide at high concentration inhibits UPS and mTOR, activates autophagy, and increases HSP70 levels in HepG2 cells, and N-acetylcysteine reduces UPS inhibition and HSP70 levels in acrylamide-treated cells.

Acrylamide-derived cytotoxic, anti-proliferative, and apoptotic effects on A549 cells

BACKGROUND

Acrylamide is a very common compound even reaching up to our daily foods. It has been studied in a wealth of cell lines on which it proved to have various toxic effects. Among these cell lines, human lung adenocarcinoma cell line (A549) is one of that on which acrylamide's toxicity has not been studied well yet.

AIM

We intended to determine the half maximal inhibitory concentration (IC₅₀) dose of acrylamide and to investigate its cytotoxic, anti-proliferative and apoptotic effects on A549 cells.

METHODS

We determined the IC₅₀ dose by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Then, the mode of cell death was evaluated by flow cytometry using Annexin-V fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. Next, we performed transmission electron microscopy (TEM) and confocal microscopy analyses for morphological alterations and apoptotic indices.

RESULTS

According to the MTT assay results, A549 cell viability decreases proportionally with increasing acrylamide concentrations and IC₅₀ for A549 was 4.6 mM for 24 h. Annexin-V FITC/PI assay results indicated that acrylamide induces apoptosis in 64% of the A549 cells. TEM and confocal microscopy analyses showed nuclear condensations, fragmentations, cytoskeleton laceration, and membrane blebbing, which are morphological characteristics of apoptosis.

CONCLUSION

Our research suggests that acrylamide causes cytotoxic, anti-proliferative, and apoptotic effects on A549 cells at 4.6 mM IC₅₀ dose in 24 h.

Astrocytes release HspB1 in response to amyloid-β exposure in vitro

Although heat shock proteins are thought to function primarily as intracellular chaperones, the release and potential extracellular functions of heat shock proteins have been the focus of an increasing number of studies. Our particular interest is HspB1 (Hsp25/27) and as astrocytes are an in vivo source of HspB1 it is a reasonable possibility they could release HspB1 in response to local stresses. Using primary cultures of rat cortical astrocytes, we investigated the extracellular release of HspB1 with exposure to amyloid-β (Aβ). In order to assess potential mechanisms of release, we cotreated the cells with compounds that can modulate protein secretion including Brefeldin A, Methyl β-cyclodextrin, and MAP kinase inhibitors. Exposure to Aβ (0.1, 1.0, 2.0 μM) for 24-48 h resulted in a selective release of HspB1 that was insensitive to BFA treatment; none of the other inhibitors had any detectable influence. Protease protection assays indicated that some of the released HspB1 was associated with a membrane bound fraction, and analysis of exosomal preparations indicated the presence of HspB1 in exosomes. Finally, immunoprecipitation experiments demonstrated that the extracellular HspB1 was able to interact with extracellular Aβ. In summary, Aβ can stimulate release of HspB1 from astrocytes, this release is insensitive to Golgi or lipid raft disruption, and HspB1 can be found either free in the medium or associated with exosomes. This release suggests that there is a potential for extracellular HspB1 to be able to bind and sequester extracellular Aβ.

Chrysin reduced acrylamide-induced neurotoxicity in both in vitro and in vivo assessments

BACKGROUND

Acrylamide (ACR) is a well-known industrial toxic chemical that produces neurotoxicity, which is characterized by progressive central and peripheral neuronal degeneration. Chrysin is a natural, biologically active flavonoid compound, which is commonly found in many plants. The antioxidant and neuroprotective properties of chrysin have been demonstrated.

METHODS

In this study, the possible effect of chrysin on ACR-induced toxicity was evaluated in both in vitro and in vivo experiments. PC12 cells were used as a suitable in vitro model. Cells were exposed to chrysin (0.5-5 µM) for 12 and 24 h, and then ACR in IC50 concentration was added to the cells. Finally, cell viability was determined using (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay. For in vivo assay, Wistar rats were treated with ACR (50 mg/kg i.p. for 11 days) alone or in combination with chrysin (12.5, 25, and 50 mg/kg). At the end of treatment, behavioral index was evaluated.

RESULTS

ACR decreased cell viability and pre-treatment with chrysin (0.5-5 µM) significantly decreased ACR-induced cytotoxicity in the time- and dose-dependent manner. In Wistar rats, exposure to ACR significantly induced severe gait abnormalities, but treatment with chrysin (50 mg/kg) reduced ACR-induced neurotoxicity in animals.

CONCLUSION

In the current study, chrysin exhibited neuroprotective effect on PC12 cells as an in vitro model and also on Wistar rats.

Reproductive toxicity in acrylamide-treated female mice

We investigated the reproductive toxicity of acrylamide in female mice. The results from immunohistochemistry provided evidence that nitric oxide synthase (NOS) signaling was involved in the process of follicular development and atresia. Oral administration of acrylamide to female mice led to significantly reduced body weights, organ weights and the number of corpora lutea (P<0.05). Serum progesterone concentrations were significantly reduced (P<0.05) concomitant with the increasing doses of acrylamide; however, 17β-estradiol (E2) concentrations were unchanged with treatment. Measurement of NOS activities indicated that total NOS (TNOS), iNOS and eNOS activities were significantly increased (P<0.05) with increasing doses of acrylamide. The results from in vitro study indicated that acrylamide reduced the viability of mouse granulosa cells in a dose-dependent manner. In summary, acrylamide affected bodily growth and development, as well as reproductive organs, the number of corpora lutea and progesterone production in female mice, possibly acting through the NOS signaling pathway.

17AAG Treatment Accelerates Doxorubicin Induced Cellular Senescence: Hsp90 Interferes with Enforced Senescence of Tumor Cells

Hsp90 chaperone has been identified as an attractive pharmacological target to combat cancer. However, some metastatic tumors either fail to respond to Hsp90 inhibition or show recovery necessitating irreversible therapeutic strategies. In response to this enforced senescence has been proposed as an alternate strategy. Here, we demonstrate that inhibiting Hsp90 with 17AAG sensitizes human neuroblastoma to DNA damage response mediated cellular senescence. Among individual and combination drug treatments, 17AAG pre-treatment followed by doxorubicin treatment exhibited senescence-like characteristics such as increased nucleus to cytoplasm ratio, cell cycle arrest, SA-β-gal staining and the perpetual increase in SAHF. Doxorubicin induced senescence signaling was mediated by p53-p21(CIP/WAF-1) and was accelerated in the absence of functional Hsp90. Sustained p16(INK4a) and H3K4me3 expressions correlating with unaffected telomerase activation annulled replicative senescence and appraised stress induced senescence. Despite increases in [(ROS)i] and [(Ca(2+))i], a concomitant increase in cellular antioxidant defense system suggested oxidation independent senescence activation. Sustained activation of survival (Akt) and proliferative (ERK1/2) kinases fosters robustness of cells. Invigorating senescent cells with growth factor or snooping with mTOR or PI3 kinase inhibitors compromised cell survival but not senescence. Intriguingly, senescence-associated secretory factors from the senescence cells manifested established senescence in neuroblastoma, which offers clinical advantage to our approach. Our study discusses tumor selective functions of Hsp90 and discusses irrefutable strategies of Hsp90 inhibition in anticancer treatments.

Ameliorating effect of fish oil on acrylamide induced oxidative stress and neuronal apoptosis in cerebral cortex

Acrylamide (ACR) is a known industrial toxic chemical that produce neurotoxicity characterized by progressive neuronal degeneration. This study was designed to investigate the protective effect of fish oil on ACR-induced neuronal damage in Wistar rats. ACR enhances the production of reactive oxygen species and potentially affects brain. ACR administered rats showed increased levels of lipid peroxidative product, protein carbonyl content, hydroxyl radical and hydroperoxide which were significantly modulated by the supplementation of fish oil. The activities of enzymic antioxidants and levels of reduced glutathione were markedly lowered in ACR-induced rats; fish oil treatment augmented these antioxidant levels in cortex. Free radicals generated during ACR administration reduced the activities of membrane adenosine triphosphatases and acetylcholine esterase. Fish oil enhanced the activities of these enzymes near normal level. Histological observation represented the protective role of fish oil in ACR-induced neuronal damage. Fish oil reduced the ACR-induced apoptosis through the modulation in expressions of B-cell lymphoma 2 (Bcl2)-associated X protein and Bcl2-associated death promoter. Further, fish oil increases the expression of heat shock protein 27 (Hsp27) in ACR-induced rats. This study provides evidence for the neuroprotective effect of fish oil on ACR-induced neurotoxicity by reducing oxidative stress and apoptosis with modulation in the expression of Hsp27.

Effect of sub-acute exposure to acrylamide on GABAergic neurons and astrocytes in weaning rat cerebellum

Occupational exposure and experimental intoxication of acrylamide (ACR) can produce skeletal muscle weakness and ataxia. In this study, we tested whether ACR would affect cerebellar function through the regulation of gamma-aminobutyric acid (GABA) and glial fibrillary acidic protein (GFAP) expression in cerebellum. Weaning male Sprague-Dawley rats were gavaged with ACR (5, 15, 30 mg/kg, 5 days per week) or saline for 4 weeks. Effects of ACR on the cerebellum were observed. For the 5 mg/kg group, no obvious change was observed, whereas moderate and severe ataxia were observed in the 15 mg/kg and 30 mg/kg groups, respectively. For the 15 mg/kg and 30 mg/kg groups, cerebellum concentrations of glutamate and GABA were dose-dependently decreased and increased, respectively. Moreover, the expression of GABA, the GABAergic presynaptic marker glutamate acid decarboxylase-65 (GAD65) and GFAP were significantly increased in those 2 groups. The results suggested that weaning rats were sensitive to ACR and that the toxic effects of ACR on the cerebellum may be associated with the increased expression of GABA and reactive astrocytes hypertrophy.

Toxicological effects of acrylamide on the reproductive system of weaning male rats

It has been reported that acrylamide can be detected in starchy food treated by high temperature (120 °C). People could be exposed to acrylamide in factory, laboratory, or even in daily life via diet and drinking water. Recently, the toxicity of acrylamide receives more attention. In addition to the neurotoxicity in humans, other toxic effects of acrylamide are worth further investigation. In this study, we investigated whether acrylamide affected the male reproductive system using high-performance liquid chromatography. In this study, the reproductive toxicity of acrylamide was observed in 3-week-old weaning male Sprague-Dawley rats treated with acrylamide at various doses (0, 5, 15 or 30 mg/kg/day). The results showed that food availability and reproductive organ indexes of the weaning male rats decreased. Levels of follicle-stimulating hormone and testosterone in serum increased while luteinizing hormone in serum decreased. The histopathological lesions and abnormal sperms presented in weaning rats after acrylamide treatment. The results suggested that there is a toxicological effect of acrylamide on the reproductive system of weaning male rats. Based on the findings above, we suggested that more attention should be paid to the toxicological study of acrylamide on weaning male rats or human beings, rather than just on adult male animals.