Browsing by Issue Date, starting with "2021-04-20"
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- Quaternary mixtures of TiO2NP, CeO2NP, arsenic, and mercury potentiate A549, HepG2 and SH-SY5Y cells cytotoxicityPublication . Rosário, Fernanda; Costa, Carla; Teixeira, João; Reis, Ana TeresaIntroduction: Nanoparticles (NP) released to the environment interact with pre-existing contaminants, potentially leading to cytotoxicity and raising concerns regarding human safety to co- exposure to multiple chemicals. This work assesses and compares viability of A549, HepG2 and SH-SY5Y cells after short (24h; WST-1 assay) and long-term (7 days; clonogenic assay) exposure to single and quaternary mixtures of: titanium dioxide nanoparticles (TiO2NP) 0.75; 75 mg/L; cerium oxide nanoparticles (CeO2NP) 0.1; 10 μg/L; arsenic (As) 0.01; 0.75; 2.5 mg/L; and mercury (Hg) 0.5; 10; 20 mg/L. Mixtures were divided in four groups: low, mid-low, mid- high and high.
- Evaluation of cytotoxic and genotoxic effects of functionalized nanocellulose in a co-culture system approaching the lung environmentPublication . Pinto, Fátima; Ventura, Célia; Lourenço, Ana Filipa; Ferreira, Paulo J.T.; Louro, Henriqueta; Silva, Maria JoãoIntroduction: Nanocelluloses, obtained from different sources and by various methods and holding different functionalization are innovative environmentally friendly materials in both pure and composite forms that hold great promise for industrial or advanced biomedical applications. Based on previous knowledge on other nanofibers e.g., carbon nanotubes, revealing toxicity at cellular and organismal levels, there is a need to evaluate the toxic potential of new nanocelluloses, particularly cellulose nanofibrils (CNF), before entering the market. In this work, three different types of nanocelluloses produced from Eucalyptus globulus bleached kraft pulp but differing in important physicochemical properties such as the carboxyl content (CCOOH), degree of polymerization (DP), morphology, specific surface area and size of fibrils, were investigated regarding cyto- and genotoxic effects in human alveolar cells and in a co-culture of human alveolar cells (A549 cells) and THP-1 differentiated macrophages. Results: A preliminary evaluation of the cytotoxicity in A549 by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed that all nanocellulose samples showed no toxicity over the examined concentration range during a 24h exposure period. The genotoxicity of the nanocellulose samples was assessed through the cytokinesis-blocked micronucleus assay in A549 co-cultured with THP-1 cells and exposed to 1.5, 3, 6, 12.5, and 25 μg/cm2 of each nanocellulose for 24h. Preliminary results showed no alterations in the frequency of micronucleated binuceated cells for all tested concentrations in one sample of CNF produced with a catalytic oxidation with TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) radical (T1300). Moreover, the cytokinesis-block proliferation index of exposed A549 cells did not show differences as compared with non-exposed cells, in line with the MTT results, suggesting that the tested nanocelluloses do not affect A549 cells proliferation. Conclusions: Preliminary results suggest that T1300 sample do not present cytotoxicity or genotoxicity in the examined concentration range and exposure time, as compared to controls. The other two samples are still being investigated.
- Increased antibacterial properties of indoline-derived phenolic Mannich basesPublication . Rimpiläinen, Tatu; Nunes, Alexandra; Calado, Rita; Fernandes, Ana S.; Andrade, Joana; Ntungwe, Epole; Spengler, Gabriella; Szemerédi, Nikoletta; Rodrigues, João; Gomes, João Paulo; Rijo, Patricia; Candeias, Nuno R.The search for antibacterial agents for the combat of nosocomial infections is a timely problem, as antibiotic-resistant bacteria continue to thrive. The effect of indoline substituents on the antibacterial properties of aminoalkylphenols was studied, leading to the development of a library of compounds with minimum inhibitory concentrations (MICs) as low as 1.18 μM. Two novel aminoalkylphenols were identified as particularly promising, after MIC and minimum bactericidal concentrations (MBC) determination against a panel of reference strain Gram-positive bacteria, and further confirmed against 40 clinical isolates (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium, and Listeria monocytogenes). The same two aminoalkylphenols displayed low toxicity against two in vivo models (Artemia salina brine shrimp and Saccharomyces cerevisiae). The in vitro cytotoxicity evaluation (on human keratinocytes and human embryonic lung fibroblast cell lines) of the same compounds was also carried out. They demonstrated a particularly toxic effect on the fibroblast cell lines, with IC50 in the 1.7-5.1 μM range, thus narrowing their clinical use. The desired increase in the antibacterial properties of the aminoalkylphenols, particularly indoline-derived phenolic Mannich bases, was reached by introducing an additional nitro group in the indolinyl substituent or by the replacement of a methyl by a bioisosteric trifluoromethyl substituent in the benzyl group introduced through use of boronic acids in the Petasis borono-Mannich reaction. Notably, the introduction of an additional nitro moiety did not confer added toxicity to the aminoalkylphenols.
- Titanium dioxide nanomaterials - induced DNA damage in intestinal cells following simulated in vitro digestionPublication . Vieira, Adriana; Rolo, Dora; Vital, Nádia; Martins, Carla; Assunção, Ricardo; Alvito, Paula; Gonçalves, Lídia; Bettencourt, Ana; Silva, Maria João; Louro, HenriquetaIntroduction: The increased use of titanium dioxide nanomaterials (TiO2) in food products has raised oral exposure to those nanomaterials, with subsequent risks to human health, particularly genotoxicity and, ultimately, cancer development. In humans, the digestion process may modify the physicochemical properties of TiO2, thereby shaping the potential biological outcomes. Thus, such process should be considered when assessing their hazard upon oral exposure. This work aimed to investigate the genotoxic effects of three TiO2 (NM-102, NM-103 and NM-105, JRC repository) after the simulation of the human digestive process using the standardized INFOGEST in vitro digestion method. The secondary physicochemical properties and DNA damage levels, using the comet assay, were analysed in two intestinal cell lines exposed for 24h to digested or undigested TiO2. Results: An increase in the level of DNA strand breaks in two intestinal cell lines(Caco-2 and HT29-MTX-E12) was observed after exposure to digested NM-105, concomitantly with a decrease in its hydrodynamic size, comparatively to the undigested nanomaterial. Moreover, the digested NM-103 induced DNA damage in Caco-2 cells whereas the undigested nanomaterial did not. The FPG-modified comet assay also revealed an increase in oxidative DNA lesions upon treatment of Caco-2 with NM-103 and HT29-MTX-E12 with NM-102. Conclusions: One of the digested TiO2(NM-105) can be classified as potentially genotoxic in both cell lines, while the digested NM-103 induced an equivocal genotoxic response in Caco-2 cells. Therefore, the digestion simulation is of relevance to investigate the potential genotoxic effects of ingested nanomaterials.
- Constructing a cardiac cell model from a patient with Fabry diseasePublication . Duarte, Ana Joana; Ribeiro, Diogo; Amaral, Olga• We successfully achieve an iPSC line from a patient with Fabry Disease • Our line has the characteristics of stem cells and has the hability to differentiate into the 3 germ layers • After induction with specific cardiac effectors we achieved beating iPSC-CMs
- Cellular effects of Titanium Dioxide Nanoparticles in the intestinePublication . Rolo, Dora; Pereira, Joana F.S.; Matos, Paulo; Gonçalves, Lídia; Bettencourt, Ana Francisca; Jordan, Peter; Silva, Maria João; Louro, HenriquetaIntroduction: The increased use of titanium dioxide nanoparticles (TiO2-NPs) as a food additive demands a thorough assessment of their potential risk for human health. Via oral exposure they may lead to adverse local or systemic outcomes, and few studies have focused on the cellular internalization mechanisms (endocytosis) of TiO2-NPs. The objective was to analyze the mechanisms by which TiO2-NPs (NM-102, NM-103 and NM-105, JRC repository) translocate by the intestinal epithelium layer, using monolayers of human intestinal cell lines (Caco-2 and HT29-MTX), as well as polarized Caco-2 cells, and co-cultures of both cells. Results: We evaluated cell differentiation by transepithelial resistance measurements and the translocation of TiO2-NPs tagged with alizarin through the intestinal barrier by confocal microscopy and we confirmed the internalization of the TiO2-NPs in both cell line models. Co-localization studies suggested that the smallest TiO2-NPs were internalized into EEA1-positive early-endosomes and accumulate in late endosomes (Rab7), with only a small fraction following the degradative pathway to the lysosome (LAMP1). This suggested that at least part of the TiO2-NPs could be redirected to the secretory pathway. Consistently, we detected fluorescence passing from the apical (AP) to the basolateral (BL) chamber, depending on the characteristics of cell model and TiO2-NPs tested. Conclusions: Small TiO2-NPs were endocytosed by Caco-2 cells, with an increase in particle diameter suggesting intracellular aggregation, whereas larger agglomerates deposited mainly extracellularly. Following endocytosis, TiO2 NPs were trafficked through different intracellular compartments including early and late endosomes/endo-lysosomes, with part being subjected to AP to BL transport.