scholarly journals 1,800 MHz Radiofrequency Electromagnetic Irradiation Impairs Neurite Outgrowth With a Decrease in Rap1-GTP in Primary Mouse Hippocampal Neurons and Neuro2a Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Yanqi Li ◽  
Ping Deng ◽  
Chunhai Chen ◽  
Qinlong Ma ◽  
Huifeng Pi ◽  
...  
Keyword(s):  
Protein Expression ◽  
Cell Viability ◽  
Brain Development ◽  
Neurite Outgrowth ◽  
Hippocampal Neurons ◽  
Neurite Length ◽  
Primary Mouse ◽  
Primary Hippocampal Neurons ◽  
Neuro2a Cells

Background: With the global popularity of communication devices such as mobile phones, there are increasing concerns regarding the effect of radiofrequency electromagnetic radiation (RF-EMR) on the brain, one of the most important organs sensitive to RF-EMR exposure at 1,800 MHz. However, the effects of RF-EMR exposure on neuronal cells are unclear. Neurite outgrowth plays a critical role in brain development, therefore, determining the effects of 1,800 MHz RF-EMR exposure on neurite outgrowth is important for exploring its effects on brain development.Objectives: We aimed to investigate the effects of 1,800 MHz RF-EMR exposure for 48 h on neurite outgrowth in neuronal cells and to explore the associated role of the Rap1 signaling pathway.Material and Methods: Primary hippocampal neurons from C57BL/6 mice and Neuro2a cells were exposed to 1,800 MHz RF-EMR at a specific absorption rate (SAR) value of 4 W/kg for 48 h. CCK-8 assays were used to determine the cell viability after 24, 48, and 72 h of irradiation. Neurite outgrowth of primary hippocampal neurons (DIV 2) and Neuro2a cells was observed with a 20 × optical microscope and recognized by ImageJ software. Rap1a and Rap1b gene expressions were detected by real-time quantitative PCR. Rap1, Rap1a, Rap1b, Rap1GAP, and p-MEK1/2 protein expressions were detected by western blot. Rap1-GTP expression was detected by immunoprecipitation. The role of Rap1-GTP was assessed by transfecting a constitutively active mutant plasmid (Rap1-Gly_Val-GFP) into Neuro2a cells.Results: Exposure to 1,800 MHz RF-EMR for 24, 48, and 72 h at 4 W/kg did not influence cell viability. The neurite length, primary and secondary neurite numbers, and branch points of primary mouse hippocampal neurons were significantly impaired by 48-h RF-EMR exposure. The neurite-bearing cell percentage and neurite length of Neuro2a cells were also inhibited by 48-h RF-EMR exposure. Rap1 activity was inhibited by 48-h RF-EMR with no detectable alteration in either gene or protein expression of Rap1. The protein expression of Rap1GAP increased after 48-h RF-EMR exposure, while the expression of p-MEK1/2 protein decreased. Overexpression of constitutively active Rap1 reversed the decrease in Rap1-GTP and the neurite outgrowth impairment in Neuro2a cells induced by 1,800 MHz RF-EMR exposure for 48 h.Conclusion: Rap1 activity and related signaling pathways are involved in the disturbance of neurite outgrowth induced by 48-h 1,800 MHz RF-EMR exposure. The effects of RF-EMR exposure on neuronal development in infants and children deserve greater focus.

scholarly journals Deletion of the Actin-Associated Tropomyosin Tpm3 Leads to Reduced Cell Complexity in Cultured Hippocampal Neurons—New Insights into the Role of the C-Terminal Region of Tpm3.1

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 715
Author(s):  
Tamara Tomanić ◽  
Claire Martin ◽  
Holly Stefen ◽  
Esmeralda Parić ◽  
Peter Gunning ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Growth Cones ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
C Terminus ◽  
Primary Mouse ◽  
Terminal Amino

Tropomyosins (Tpms) have been described as master regulators of actin, with Tpm3 products shown to be involved in early developmental processes, and the Tpm3 isoform Tpm3.1 controlling changes in the size of neuronal growth cones and neurite growth. Here, we used primary mouse hippocampal neurons of C57/Bl6 wild type and Bl6Tpm3flox transgenic mice to carry out morphometric analyses in response to the absence of Tpm3 products, as well as to investigate the effect of C-terminal truncation on the ability of Tpm3.1 to modulate neuronal morphogenesis. We found that the knock-out of Tpm3 leads to decreased neurite length and complexity, and that the deletion of two amino acid residues at the C-terminus of Tpm3.1 leads to more detrimental changes in neurite morphology than the deletion of six amino acid residues. We also found that Tpm3.1 that lacks the 6 C-terminal amino acid residues does not associate with stress fibres, does not segregate to the tips of neurites, and does not impact the amount of the filamentous actin pool at the axonal growth cones, as opposed to Tpm3.1, which lacks the two C-terminal amino acid residues. Our study provides further insight into the role of both Tpm3 products and the C-terminus of Tpm3.1, and it forms the basis for future studies that aim to identify the molecular mechanisms underlying Tpm3.1 targeting to different subcellular compartments.

scholarly journals Dendrobium alkaloids decrease Aβ by regulating α- and β-secretases in hippocampal neurons of SD rats

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7627 ◽  
Author(s):  
Juan Huang ◽  
Nanqu Huang ◽  
Minghui Zhang ◽  
Jing Nie ◽  
Yunyan Xu ◽  
...  
Keyword(s):  
Protein Expression ◽  
Cell Viability ◽  
Learning And Memory ◽  
Hippocampal Neurons ◽  
Memory Function ◽  
Amyloid Β ◽  
Aging Effects ◽  
Potential Health ◽  
Sd Rats

Background Alzheimer’s disease (AD) is the primary cause of dementia in the elderly. The imbalance between production and clearance of amyloid β (Aβ) is a very early, often initiating factor in AD. Dendrobium nobile Lindl. alkaloids (DNLA) extracted from a Chinese medicinal herb, which have been shown to have anti-aging effects, protected against neuronal impairment in vivo and in vitro. Moreover, we confirmed that DNLA can improve learning and memory function in elderly normal mice, indicating that DNLA has potential health benefits. However, the underlying mechanism is unclear. Therefore, we further explored the effect of DNLA on neurons, which is closely related to learning and memory, based on Aβ. Methods We exposed cultured hippocampal neurons to DNLA to investigate the effect of DNLA on Aβ in vitro. Cell viability was evaluated by MTT assays. Proteins were analyzed by Western blot analysis. Results The cell viability of hippocampal neurons was not changed significantly after treatment with DNLA. But DNLA reduced the protein expression of amyloid precursor protein (APP), disintegrin and metalloprotease 10 (ADAM10), β-site APP cleaving enzyme 1 (BACE1) and Aβ1–42 of hippocampal neurons in rats and increased the protein expression of ADAM17. Conclusions DNLA decreases Aβ by regulating α- and β-secretase in hippocampal neurons of SD rats.

scholarly journals Overexpression of the dystrophins Dp40 and Dp40L170P modifies neurite outgrowth and the protein expression profile of PC12 cells

2021 ◽  
Author(s):  
César García-Cruz ◽  
Candelaria Merino-Jiménez ◽  
Jorge Aragón ◽  
Víctor Ceja ◽  
Brenda González-Assad ◽  
...  
Keyword(s):  
Protein Expression ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Expression Profile ◽  
Hippocampal Neurons ◽  
Protein Expression Profile ◽  
Neurofilament Light Chain ◽  
Two Dimensional Gel Electrophoresis ◽  
Neurofilament Light ◽  
Differentiated Cells

Abstract Dp40 is ubiquitously expressed, including in the central nervous system. Dp40 mRNA and protein are detected in the early stages and postnatal stages of the mouse brain, respectively. In addition to being present in the nucleus, membrane, and cytoplasm, Dp40 is detected in neurites and postsynaptic spines in hippocampal neurons. Although Dp40 is expressed from the same promoter as Dp71, its role in the cognitive impairment present in Duchenne muscular dystrophy patients is still unknown. Here, we studied the effects of overexpression of Dp40 and Dp40L170P (a mutant of Dp40) during the neuronal differentiation process of PC12 Tet-On cells. We found that Dp40 overexpression increased the percentage of PC12 cells with neurites and neurite length, while Dp40L170P overexpression decreased them compared to Dp40 overexpression. Two-dimensional gel electrophoresis analysis carried out in nerve growth factor-differentiated PC12-Dp40L170P cells showed that the protein expression profile was modified compared to that of the control cells (PC12 Tet-On). The proteins with the highest upregulated expression were α-internexin and S100a6, which are involved in cytoskeletal structure. The expression of vesicle-associated membrane proteins increased in differentiated PC12-Dp40 cells, in contrast to PC12-Dp40L170P cells, while neurofilament light-chain was decreased in both differentiated cells. HspB1 was absent in undifferentiated cells and weakly detected in all differentiated cells. These results suggest that the subcellular distribution and expression of Dp40 has an important role in the neurite outgrowth of PC12 cells through the regulation of proteins involved in neurofilaments and exocytosis of synaptic vesicles, functions that might be affected in PC12-Dp40L170P.

scholarly journals Absence of Thyroid Hormone Induced Delayed Dendritic Arborization in Mouse Primary Hippocampal Neurons Through Insufficient Expression of Brain-Derived Neurotrophic Factor

2021 ◽  
Vol 12 ◽  
Author(s):  
Hiroyuki Yajima ◽  
Izuki Amano ◽  
Sumiyasu Ishii ◽  
Tetsushi Sadakata ◽  
Wataru Miyazaki ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Neurotrophic Factor ◽  
Hippocampal Neurons ◽  
Brain Derived Neurotrophic Factor ◽  
Mrna Levels ◽  
Protein Levels ◽  
Primary Hippocampal Neurons ◽  
Developmental Impairment

Thyroid hormone (TH) plays important roles in the developing brain. TH deficiency in early life leads to severe developmental impairment in the hippocampus. However, the mechanisms of TH action in the developing hippocampus are still largely unknown. In this study, we generated 3,5,3’-tri-iodo-l-thyronine (T3)-free neuronal supplement, based on the composition of neuronal supplement 21 (NS21), to examine the effect of TH in the developing hippocampus using primary cultured neurons. Effects of TH on neurons were compared between cultures in this T3-free culture medium (-T3 group) and a medium in which T3 was added (+T3 group). Morphometric analysis and RT-qPCR were performed on 7, 10, and 14 days in vitro (DIV). On 10 DIV, a decreased dendrite arborization in -T3 group was observed. Such difference was not observed on 7 and 14 DIV. Brain-derived neurotrophic factor (Bdnf) mRNA levels also decreased significantly in -T3 group on 10 DIV. We then confirmed protein levels of phosphorylated neurotrophic tyrosine kinase type 2 (NTRK2, TRKB), which is a receptor for BDNF, on 10 DIV by immunocytochemistry and Western blot analysis. Phosphorylated NTRK2 levels significantly decreased in -T3 group compared to +T3 group on 10 DIV. Considering the role of BDNF on neurodevelopment, we examined its involvement by adding BDNF on 8 and 9 DIV. Addition of 10 ng/ml BDNF recovered the suppressed dendrite arborization induced by T3 deficiency on 10 DIV. We show that the lack of TH induces a developmental delay in primary hippocampal neurons, likely caused through a decreased Bdnf expression. Thus, BDNF may play a role in TH-regulated dendritogenesis.

scholarly journals CD82 Aggravates Sevoflurane - Induced Neurotoxicity by Regulating TRPM7 in Developing Neurons

2020 ◽  
Keyword(s):  
Protein Expression ◽  
Cell Viability ◽  
Cell Apoptosis ◽  
Hippocampal Neurons ◽  
Transient Receptor Potential ◽  
Time Dependent ◽  
Dependent Manner ◽  
Over Expression ◽  
Transient Receptor Potential Melastatin ◽  
Developing Neurons

Background: Sevoflurane, a commonly used anesthetic in neonatal, could induce neurotoxicity in newborn animals. CD82 was found to be involved in age-related cognitive impairment. However, the role of CD82 in sevoflurane-induced neurotoxicity remains elusive. Methods: Hippocampal neurons were isolated from neonatal rats (postnatal day 1 or 2), and then exposed to 1.8 % sevoflurane for 6, 12, 24 or 48 hours. Neurons were pre-transfected with siRNA targeting CD82 (siCD82) or co-transfected with siTRPM7 (transient receptor potential melastatin 7) and pcDNA 3.1-CD82, and then exposed with sevoflurane (1.8%, 12 hours). Cell viability of the neurons was analyzed with MTT assay, and cell apoptosis was determined by flow cytometry. Protein expression was analyzed by western blot. Results: Sevoflurane exposure decreased cell viability of the developing hippocampal neurons in a time-dependent manner. Protein expressions of CD82 and TRPM7 were increased in neurons post sevoflurane exposure in a time-dependent manner. Pre-transfection of siCD82 attenuated sevoflurane-induced decrease in cell viability and increase in cell apoptosis in the neurons. Moreover, knockdown of CD82 reversed the promoting effects of sevoflurane on protein expression of cleaved TRPM7 and cleaved caspase-3. Over-expression of CD82 aggravated sevoflurane-induced decrease in cell viability and increase in cell apoptosis in neurons, while knockdown of TRPM7 counteracted with the effects of CD82 over-expression on sevoflurane-induced developing neurons. Conclusion: Sevoflurane exposure increased the expression of CD82 and TRPM7 in developing hippocampal neurons, decreased cell viability and promoted the cell apoptosis. Knockdown of CD82 partially ameliorated sevoflurane-induced neurotoxicity by down-regulation of cleaved TRPM7 in the developing neurons.

scholarly journals S100A12 protein is a strong inducer of neurite outgrowth from primary hippocampal neurons

2008 ◽  
Vol 79 (4) ◽  
pp. 767-776 ◽  
Author(s):  
Sanne E. Mikkelsen ◽  
Vera Novitskaya ◽  
Marina Kriajevska ◽  
Vladimir Berezin ◽  
Elisabeth Bock ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Hippocampal Neurons ◽  
S100a12 Protein ◽  
Primary Hippocampal Neurons

scholarly journals Suppression of kinesin expression in cultured hippocampal neurons using antisense oligonucleotides.

1992 ◽  
Vol 117 (3) ◽  
pp. 595-606 ◽  
Author(s):  
A Ferreira ◽  
J Niclas ◽  
R D Vale ◽  
G Banker ◽  
K S Kosik
Keyword(s):  
Neurite Outgrowth ◽  
Cell Body ◽  
Heavy Chain ◽  
Antisense Oligonucleotides ◽  
Hippocampal Neurons ◽  
Full Recovery ◽  
Synapsin I ◽  
Neurite Length ◽  
Protein Levels ◽  
Cultured Hippocampal Neurons

Kinesin, a microtubule-based force-generating molecule, is thought to translocate organelles along microtubules. To examine the function of kinesin in neurons, we sought to suppress kinesin heavy chain (KHC) expression in cultured hippocampal neurons using antisense oligonucleotides and study the phenotype of these KHC "null" cells. Two different antisense oligonucleotides complementary to the KHC sequence reduced the protein levels of the heavy chain by greater than 95% within 24 h after application and produced identical phenotypes. After inhibition of KHC expression for 24 or 48 h, neurons extended an array of neurites often with one neurite longer than the others; however, the length of all these neurites was significantly reduced. Inhibition of KHC expression also altered the distribution of GAP-43 and synapsin I, two proteins thought to be transported in association with membranous organelles. These proteins, which are normally localized at the tips of growing neurites, were confined to the cell body in antisense-treated cells. Treatment of the cells with the corresponding sense oligonucleotides affected neither the distribution of GAP-43 and synapsin I, nor the length of neurites. A full recovery of neurite length occurred after removal of the antisense oligonucleotides from the medium. These data indicate that KHC plays a role in the anterograde translocation of vesicles containing GAP-43 and synapsin I. A deficiency in vesicle delivery may also explain the inhibition of neurite outgrowth. Despite the inhibition of KHC and the failure of GAP-43 and synapsin I to move out of the cell body, hippocampal neurons can extend processes and acquire as asymmetric morphology.

scholarly journals 3-Iodothyronamine and 3,5,3′-triiodo-L-thyronine reduce SIRT1 protein expression in the HepG2 cell line

2020 ◽  
Vol 41 (1) ◽  
Author(s):  
Ginevra Sacripanti ◽  
Leonardo Lorenzini ◽  
Lavinia Bandini ◽  
Sabina Frascarelli ◽  
Riccardo Zucchi ◽  
...  
Keyword(s):  
Protein Expression ◽  
Cell Viability ◽  
Cell Line ◽  
Potential Role ◽  
Colorimetric Assay ◽  
Tumor Cell Line ◽  
Rat Hepatocytes ◽  
Carcinoma Cells ◽  
Primary Rat Hepatocytes

AbstractBackground3-Iodothyronamine (T1AM) is an endogenous messenger chemically related to thyroid hormone. Recent results indicate significant transcriptional effects of chronic T1AM administration involving the protein family of sirtuins, which regulate important metabolic pathways and tumor progression. Therefore, the aim of this work was to compare the effect of exogenous T1AM and 3,5,3′-triiodo-L-thyronine (T3) chronic treatment on mammalian sirtuin expression in hepatocellular carcinoma cells (HepG2) and in primary rat hepatocytes at micromolar concentrations.Materials and methodsSirtuin (SIRT) activity and expression were determined using a colorimetric assay and Western blot analysis, respectively, in cells treated for 24 h with 1–20 μM T1AM or T3. In addition, cell viability was evaluated by the MTTtest upon 24 h of treatment with 0.1–20 μM T1AM or T3.ResultsIn HepG2, T1AM significantly reduced SIRT 1 (20 μM) and SIRT4 (10–20 μM) protein expression, while T3 strongly decreased the expression of SIRT1 (20 μM) and SIRT2 (any tested concentration). In primary rat hepatocytes, T3 decreased SIRT2 expression and cellular nicotinamide adenine dinucleotide (NAD) concentration, while on sirtuin activity it showed opposite effects, depending on the evaluated cell fraction. The extent of MTT staining was moderately but significantly reduced by T1AM, particularly in HepG2 cells, whereas T3 reduced cell viability only in the tumor cell line.ConclusionsT1AM and T3 downregulated the expression of sirtuins, mainly SIRT1, in hepatocytes, albeit in different ways. Differences in mechanisms are only observational, and further investigations are required to highlight the potential role of T1AM and T3 in modulating sirtuin expression and, therefore, in regulating cell cycle or tumorigenesis.

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