Acrylamide acute neurotoxicity in adult zebrafish

Un articulo indexadoAcute exposure to acrylamide (ACR), a type-2 alkene, may lead to a ataxia, skeletal muscles weakness and numbness of the extremities in human and laboratory animals. In the present manuscript, ACR acute neurotoxicity has been characterized in adult zebrafish, a vertebrate model increasingly used in human neuropharmacology and toxicology research. At behavioral level, ACR-treated animals exhibited “depression-like” phenotype comorbid with anxiety behavior. At transcriptional level, ACR induced down-regulation of regeneration-associated genes and up-regulation of oligodendrocytes and reactive astrocytes markers, altering also the expression of genes involved in the presynaptic vesicle cycling. ACR induced also significant changes in zebrafish brain proteome and formed adducts with selected cysteine residues of specific proteins, some of them essential for the presynaptic function. Finally, the metabolomics analysis shows a depletion in the monoamine neurotransmitters, consistent with the comorbid depression and anxiety disorder, in the brain of the exposed fish.Conacy

Therapeutic potential of N-acetylcysteine in acrylamide acute neurotoxicity in adult zebrafish

Two essential key events in acrylamide (ACR) acute neurotoxicity are the formation of adducts with nucleophilic sulfhydryl groups on cysteine residues of selected proteins in the synaptic terminals and the depletion of the glutathione (GSx) stores in neural tissue. The use of N-acetylcysteine (NAC) has been recently proposed as a potential antidote against ACR neurotoxicity, as this chemical is not only a well-known precursor of the reduced form of glutathione (GSH), but also is an scavenger of soft electrophiles such as ACR. In this study, the suitability of 0.3 and 0.75 mM NAC to protect against the neurotoxic effect of 0.75 mM ACR has been tested in vivo in adult zebrafish. NAC provided only a mild to negligible protection against the changes induced by ACR in the motor function, behavior, transcriptome and proteome. The permeability of NAC to cross blood-brain barrier (BBB) was assessed, as well as the ACR-scavenging activity and the gamma-glutamyl-cysteine ligase (γ-GCL) and acylase I activities. The results show that ACR not only depletes GSx levels but also inhibits it synthesis from NAC/cysteine, having a dramatic effect over the glutathione system. Moreover, results indicate a very low NAC uptake to the brain, probably by a combination of low BBB permeability and high deacylation of NAC during the intestinal absorption. These results strongly suggest that the use of NAC is not indicated in ACR acute neurotoxicity treatment.This work was supported by the NATO SfP project MD.SFPP 984777 (D.R.) and the Spanish Government (CTM2017-83242-R; D.R.). M.F acknowledges financial support from the Beatriu de Pinós programme (Grant No. 2016 BP 00233) provided by the Secretariat of Universities and Research department of the Ministry for Business and Knowledge, Catalonia Government. Mention of specific products or trade names does not indicate endorsement by the US federal government.Peer reviewe

Nitrosothiol-Trapping-Based Proteomic Analysis of S-Nitrosylation in Human Lung Carcinoma Cells.

Nitrosylation of cysteines residues (S-nitrosylation) mediates many of the cellular effects of nitric oxide in normal and diseased cells. Recent research indicates that S-nitrosylation of certain proteins could play a role in tumor progression and responsiveness to therapy. However, the protein targets of S-nitrosylation in cancer cells remain largely unidentified. In this study, we used our recently developed nitrosothiol trapping approach to explore the nitrosoproteome of human A549 lung carcinoma cells treated with S-nitrosocysteine or pro-inflammatory cytokines. Using this approach, we identified about 300 putative nitrosylation targets in S-nitrosocysteine-treated A549 cells and approximately 400 targets in cytokine-stimulated cells. Among the more than 500 proteins identified in the two screens, the majority represent novel targets of S-nitrosylation, as revealed by comparison with publicly available nitrosoproteomic data. By coupling the trapping procedure with differential thiol labeling, we identified nearly 300 potential nitrosylation sites in about 150 proteins. The proteomic results were validated for several proteins by an independent approach. Bioinformatic analysis highlighted important cellular pathways that are targeted by S-nitrosylation, notably, cell cycle and inflammatory signaling. Taken together, our results identify new molecular targets of nitric oxide in lung cancer cells and suggest that S-nitrosylation may regulate signaling pathways that are critically involved in lung cancer progression

Correction: Nitrosothiol-Trapping-Based Proteomic Analysis of S-Nitrosylation in Human Lung Carcinoma Cells.

[This corrects the article DOI: 10.1371/journal.pone.0169862.]

Dietary transforming growth factor-beta 2 (TGF-β2) supplementation reduces methotrexate-induced intestinal mucosal injury in a rat.

BACKGROUND/AIMS: Dietary supplementation with transforming growth factor-beta (TGF-β) has been proven to minimize intestinal damage and facilitate regeneration after mucosal injury. In the present study, we evaluated the effects of oral TGF-β2 supplementation on intestinal structural changes, enterocyte proliferation and apoptosis following methotrexate (MTX)-induced intestinal damage in a rat and in a cell culture model. METHODS: Caco-2 cells were treated with MTX and were incubated with increasing concentrations of TGF-β2. Cell apoptosis was assessed using FACS analysis by annexin staining and cell viability was monitored using Trypan Blue assay. Male rats were divided into four experimental groups: Control rats, CONTR- TGF-β rats were treated with diet enriched with TGF-β2, MTX rats were treated with a single dose of methotrexate, and MTX- TGF-β rats were treated with diet enriched with TGF-β2. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined at sacrifice. Real Time PCR and Western blot were used to determine bax and bcl-2 mRNA, p-ERK, β-catenin, IL-1B and bax protein expression. RESULTS: Treatment of MTX-pretreated Caco-2 cells with TGF-B2 resulted in increased cell viability and decreased cell apoptosis. Treatment of MTX-rats with TGF-β2 resulted in a significant increase in bowel and mucosal weight, DNA and protein content, villus-height (ileum), crypt-depth (jejunum), decreased intestinal-injury score, decreased level of apoptosis and increased cell proliferation in jejunum and ileum compared to the untreated MTX group. MTX-TGF-β2 rats demonstrated a lower bax mRNA and protein levels as well as increased bcl-2 mRNA levels in jejunum and ileum compared to MTX group. Treatment with TGF-β2 also led to increased pERK, IL-1B and β-catenin protein levels in intestinal mucosa. CONCLUSIONS: Treatment with TGF-β2 prevents mucosal-injury, enhances p-ERK and β-catenin induced enterocyte proliferation, inhibits enterocyte apoptosis and improves intestinal recovery following MTX-induced intestinal-mucositis in rats

SNO trapping-based analysis of S-nitrosylation in A549 cells.

<p><b>(</b>A) Schematic of the proteomic approach. Digitonin cell lysates, obtained from A549 treated with NO donor or with cytokines are incubated with a thioredoxin (Trx) trap mutant, Trx(C35S). In the trap mutant the resolving cysteine is replaced by serine (-OH). The protein also contains a streptavidin binding peptide. Trx(C35S) forms mixed disulfide bonds with nitrosylated substrates and the resulting complexes are pulled-down using avidin agarose. Identification of nitrosylation sites is assisted by differential thiol labeling, involving the sequential application of N-ethylmaleimide (NEM) and iodoacetamide (IAM). Proteins captured in the Trx pull-down are analyzed by SDS-PAGE or liquid chromatography-tandem mass spectrometry (LC-MS/MS). (B) A549 cells were treated with or without 500 μM S-nitrosocysteine (CysNO) for 10 min and thereafter digitonin lysates were incubated with Trx(C35S). Proteins captured by Trx were released by DTT and then analyzed by SDS-PAGE. Gels were stained with Krypton fluorescent protein stain and visualized using the Odyssey infrared imaging system. (C) A549 cells were treated for 72 h with LPS (0.5 mg/ml) and a cytokine mixture that included TNFα (20 ng/ml), IFN-γ (10 ng/ml) and IL-1β (10 ng/ml). Trx-based trapping of nitrosylated proteins was performed as in B.</p

Validation of the proteomic results for selected proteins.

<p>A549 cells were treated with or without the CysNO (500 μM; 10 min). The nitrosylation level of galectin-1, NEDD4 and serpin B6 was determined using the biotin-switch assay in the presence or absence of ascorbate.</p

KEGG pathway enrichment and protein interaction analysis of S-nitrosylation in A549 cells.

<p><b>(</b>A) Overrepresented KEGG pathways among the identified candidate SNO proteins, ranked by the normalized enrichment fold (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169862#sec002" target="_blank">Materials and Methods</a> for details). Proteins were classified into different categories based on KEGG annotations and using the Genecodis algorithm (see also Sheet I in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169862#pone.0169862.s002" target="_blank">S1 Table</a>). (B) SNO proteins identified in the cytokine data set tend to be functionally related based on protein interaction networks. The diagram shows all high-confidence protein-protein interactions from the STRING interaction database [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169862#pone.0169862.ref034" target="_blank">34</a>].</p