Effects of Acrylamide on Primary Neonatal Rat Astrocyte Functions

Aschner, Michael; Wu, Qi; Friedman, Marvin A.

doi:10.1111/j.1749-6632.2005.tb00053.x

Cited by 7 publications

(6 citation statements)

References 13 publications

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“…Thus, results from the MTT assays and Ki-67 expression using longer exposure times (>24 h) in the current study provide a better correlation between ACR treatments and proliferation inhibition. Aschner et al reported that ACR promoted astrocytic cell proliferation as seen by the increase in PCNA protein expression ; the inconsistency of those results with other studies − may be due to the differences in exposure regimens and/or use of the cell types (rat primary astrocytic cells vs human astrocytoma cell lines). Therefore, the effects of ACR on cell proliferation between primary astrocytic cells and astrocytoma cells remain to be clarified.…”

Section: Discussionmentioning

confidence: 88%

“…The results of the MTT assay and Ki-67 expression suggest that ACR exposure may inhibit the proliferation of astrocytoma cells during the active phases of the cell cycle. ACR-induced cell-growth suppression had been reported in many cell types (10,23,24,36,37); but the results for astrocytic cell have not been consistent (14)(15)(16)(17). As compared with proliferating cell nuclear antigen (PCNA), Ki-67 has been recognized as a more specific indicator for the proliferative activity of human glioblastomas (38)(39)(40).…”

Section: Discussionmentioning

confidence: 99%

“…Few studies related to glial cells have been reported. No significant effects of ACR on cytoxicity and cell proliferation have been found for primary culture of rat or human astrocytoma cell lines (U-251 MG, U-373 MG, and CCF-STTG1) after exposure to ACR up to 24 h (13)(14)(15)(16). However, our previous study indicated that ACR treatments not only caused cytotoxicity but also induced astrogliotic and apoptotic responses in the human astrocytoma U-1240 MG cells (17).…”

Section: Introductionmentioning

confidence: 87%

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Proliferation Inhibition, DNA Damage, and Cell-Cycle Arrest of Human Astrocytoma Cells after Acrylamide Exposure

Chen

Tsou

Chiu

et al. 2010

Chem. Res. Toxicol.

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Acrylamide (ACR) has been recognized as a neurological and reproductive toxin in humans and laboratory animals. This study aimed to determine the effects of ACR-induced DNA damage on cell cycle regulation in human astrocytoma cell lines. Treatment of U-1240 MG cells with 2 mM ACR for 48 h resulted in a significant inhibition of cell proliferation as evaluated by Ki-67 protein expression and MTT assay. The analysis of DNA damage with the comet assay showed that treatment of the cells with 0.5, 1, and 2 mM ACR for 48 h caused significant increases in DNA damage by 3.5-, 4-, and 14-fold, respectively. Meanwhile, analysis of cell-cycle arrest with flow cytometry revealed that the ACR treatments resulted in significant increases in the G(0)/G(1)-arrested cells in a time- and dose-dependent manner. Expression of DNA damage-associated/checkpoint-related signaling molecules, including phosphorylated-p53 (pp53), p53, p21, p27, Cdk2, and cyclin D(1), in three human astrocytoma cell lines (U-1240 MG, U-251 MG, and U-87 MG) was also analyzed by immunoblotting. Treatment of the three cell lines with 2 mM ACR for 48 h caused marked increases in pp53 and Cdk2, as well as decreases in cyclin D(1) and p27. Moreover, increases in p53 and p21 were detected in both U-1240 and U-87 MG cells, whereas no marked change in p53 and a decrease in p21 were observed in U-251 MG cells. To address the involvement of ataxia telangiectasia mutated/ATM-Rad3-related (ATM/ATR) kinase in the signaling of ACR-induced G(0)/G(1) arrest, caffeine was used to block the ATM/ATR pathway in U-1240 MG cells. Caffeine significantly attenuated the ACR-induced G(0)/G(1) arrest as well as the expression of DNA damage-associated/checkpoint-related signaling molecules in a dose-dependent manner. This in vitro study clearly demonstrates the critical role of ATM/ATR in the signaling of ACR-induced cell-cycle arrest in astrocytoma cells.

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Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

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Proliferation Inhibition, DNA Damage, and Cell-Cycle Arrest of Human Astrocytoma Cells after Acrylamide Exposure

Chen

Tsou

Chiu

et al. 2010

Chem. Res. Toxicol.

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“…ASCT2 is more abundantly expressed in astrocytes than in neurons in culture [15,31]. A previous study from our laboratory has shown that exposure of astrocytes to acrylamide affects astrocytic glutamine uptake and expression of mRNA coding for Gln transporters [73] at concentrations comparable to those producing acute toxicity [7,9].…”

Section: Introductionmentioning

confidence: 99%

Methylmercury induces oxidative injury, alterations in permeability and glutamine transport in cultured astrocytes

Yin¹,

Milatović²,

Aschner³

et al. 2007

Brain Research

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160

100

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The neurotoxicity of high levels of methylmercury (MeHg) is well established both in humans and experimental animals. Astrocytes accumulate MeHg and play a prominent role in mediating MeHg toxicity in the central nervous system (CNS). Although the precise mechanisms of MeHg neurotoxicity are ill-defined, oxidative stress and altered mitochondrial and cell membrane permeability appear to be critical factors in its pathogenesis. The present study examined the effects of MeHg treatment on oxidative injury, mitochondrial inner membrane potential, glutamine uptake and expression of glutamine transporters in primary astrocyte cultures. MeHg caused a significant increase in F 2 -isoprostanes (F 2 -IsoPs), lipid peroxidation biomarkers of oxidative damage, in astrocyte cultures treated with 5 or 10 μ M MeHg for 1 or 6 hours. Consistent with this observation, MeHg induced a concentration-dependant reduction in the inner mitochondrial membrane potential (ΔΨm), as assessed by the potentiometric dye, tetramethylrhodamine ethyl ester (TMRE). Our results demonstrate that ΔΨ m is a very sensitive endpoint for MeHg toxicity, since significant reductions were observed after only 1 h exposure to concentrations of MeHg as low as 1 μ M. MeHg pretreatment (1, 5 and 10 μ M) for 30 min also inhibited the net uptake of glutamine ( 3 H-glutamine) measured at 1 min and 5 min. Expression of the mRNA coding the glutamine transporters, SNAT3/SN1 and ASCT2, was inhibited only at the highest (10 μ M) MeHg concentration, suggesting that the reduction in glutamine uptake observed after 30 min treatment with lower concentrations of MeHg (1 and 5 μ M) was not due to inhibition of transcription. Taken together, these studies demonstrate that MeHg exposure is associated with increased mitochondrial membrane permeability, alterations in glutamine/glutamate cycling, increased ROS formation and consequent oxidative injury. Ultimately, MeHg initiates multiple additive or synergistic disruptive mechanisms that lead to cellular dysfunction and cell death.Please send request for reprints to Michael Aschner, Ph.D.,

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“…Based on previous studies, acrylamide has been claimed to induce tumors at many organ sites in animals (16,29). It has also been reported that acrylamide promotes astrocytic cell proliferation and astrogliosis of astrocytic cells, which has been shown to be associated with brain tumors (2). Therefore, acrylamide-induced astrogliosis is worth further investigation.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Neurosphere Formation in Neural Stem/Progenitor Cells by Acrylamide

et al. 2015

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Previous studies showed that transplantation of cultured neural stem/progenitor cells (NSPCs) could improve functional recovery for various neurological diseases. This study aims to develop a stem cell-based model for predictive toxicology of development in the neurological system after acrylamide exposure. Treatment of mouse (KT98/F1B-GFP) and human (U-1240 MG/F1B-GFP) NSPCs with 0.5 mM acrylamide resulted in the inhibition of neurosphere formation (definition of self-renewal ability in NSPCs), but not inhibition of cell proliferation. Apoptosis and differentiation of KT98 (a precursor of KT98/F1B-GFP) and KT98/F1B-GFP are not observed in acrylamide-treated neurospheres. Analysis of secondary neurosphere formation and differentiation of neurons and glia illustrated that acrylamide-treated KT98 and KT98/F1B-GFP neurospheres retain the NSPC properties, such as self-renewal and differentiation capacity. Correlation of acrylamide-inhibited neurosphere formation with cell-cell adhesion was observed in mouse NSPCs by live cell image analysis and the presence of acrylamide. Protein expression levels of cell adhesion molecules [neural cell adhesion molecule (NCAM) and N-cadherin] and extracellular signal-regulated kinases (ERK) in acrylamide-treated KT98/F1B-GFP and U-1240 MG/F1B-GFP neurospheres demonstrated that NCAM decreased and phospho-ERK (pERK) increased, whereas expression of N-cadherin remained unchanged. Analysis of AKT (protein kinase B, PKB)/b-catenin pathway showed decrease in phospho-AKT (p-AKT) and cyclin D1 expression in acrylamide-treated neurospheres of KT98/F1B-GFP. Furthermore, PD98059, an ERK phosphorylation inhibitor, attenuated acrylamide-induced ERK phosphorylation, indicating that pERK contributed to the cell proliferation, but not in neurosphere formation in mouse NSPCs. Coimmunoprecipitation results of KT98/F1B-GFP cell lysates showed that the complex of NCAM and fibroblast growth factor receptor 1 (FGFR1) is present in the neurosphere, and the amount of this complex decreases after acrylamide treatment. Our results reveal that acrylamide inhibits neurosphere formation through the disruption of the neurosphere architecture in NSPCs. The downregulation of cell-cell adhesion resulted from decreasing the levels of NCAM as well as the formation of NCAM/ FGFR complex.

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Effects of Acrylamide on Primary Neonatal Rat Astrocyte Functions

Cited by 7 publications

References 13 publications

Proliferation Inhibition, DNA Damage, and Cell-Cycle Arrest of Human Astrocytoma Cells after Acrylamide Exposure

Proliferation Inhibition, DNA Damage, and Cell-Cycle Arrest of Human Astrocytoma Cells after Acrylamide Exposure

Methylmercury induces oxidative injury, alterations in permeability and glutamine transport in cultured astrocytes

Inhibition of Neurosphere Formation in Neural Stem/Progenitor Cells by Acrylamide

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