Browsing by Author "Ribeiro, E"
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- Cytotoxic and Genotoxic Effects of Environmental Relevant Concentrations of Bisphenol A and Interactions with DoxorubicinPublication . Ramos, C; Ladeira, C; Zeferino, S; Dias, A; Faria, I; Cristovam, E; Gomes, M; Ribeiro, EBisphenol A (BPA) is one of the most widely utilized endocrine disruptors to which humans are exposed, particularity through ingestion. BPA is an aneugenic compound with a putative association to tumorigenesis. Although extensively studied in estrogen responsive cells, information regarding its effects on cells from the upper gastrointestinal tract exposed to free/active forms of BPA is still scarce. Similarly, BPA interactions with other drugs have been neglected, although it has been suggested to have a potential role in doxorubicin (DOX) chemoresistance. This study is intended to assess potential cytotoxic and genotoxic effects of BPA, as well as its interactions with DOX, in Human epithelial type 2 cells (Hep-2) originated from a human laryngeal carcinoma and in a DNA damage responsive cell line, the human lung fibroblasts (MRC-5). Cell viability was analyzed through the resazurin assay. The G protein-coupled estrogen receptor 1 (GPER) expression was visualized by immunodetection. Genotoxicity, namely DNA damage and oxidative DNA damage, were assessed by comet assay and micronuclei induction, and mitotic disruption was evaluated cytologically by fluorescent microscopy with DAPI staining. Cytotoxicity analysis showed that exposure to BPA per se does not affect cellular viability. Nevertheless, the genotoxic analysis showed that BPA induced an increase of DNA damage in the Hep-2 cell line and in oxidative damage in the MRC-5 cell line. An increase of micronuclei was also observed in both cell lines following BPA exposure. BPA and DOX co-exposures suggested that BPA acts as an antagonist of DOX effects in both cell lines. The interaction with DOX appears to be cell type dependent, exhibiting a non-monotonic response curve in MRC-5 cells, a GPER expressing cell line. Our study emphasizes the need for a deeper knowledge of BPA interactions, particularly with chemotherapeutic agents, in the context of risk assessment and public health.
- Drug Resistance and Epigenetic Modulatory Potential of Epigallocatechin-3-Gallate Against Staphylococcus AureusPublication . Zeferino, AS; Mira, AR; Delgadinho, M; Brito, M; Ponte, T; Ribeiro, EAntimicrobial resistance of human pathogens, such as methicillin-resistant Staphylococcus aureus, is described by the World Health Organization as a health global challenge and efforts must be made for the discovery of new effective and safe compounds. This work aims to evaluate epigallocatechin-3-gallate (EGCG) epigenetic and modulatory drug potential against S. aureus in vitro and in vivo. S. aureus strains were isolated from commensal flora of healthy volunteers. Antibiotic susceptibility and synergistic assay were assessed through disk diffusion accordingly to EUCAST guidelines with and without co-exposure to EGCG at final concentrations of 250 µg/ml, 100 µg/ml, 50 µg/ml, and 25 µg/ml. Transcriptional expression of orfx, spdC, and WalKR was performed through qRT-PCR. A 90-day interventional study was performed with daily consumption of 225 mg of EGCG. Obtained data revealed a high prevalence of S. aureus colonization in healthcare workers and clearly demonstrated the antimicrobial and synergistic potential of EGCG as well as divergent resistant phenotypes associated with altered transcriptional expression of epigenetic and drug response modulators genes. Here, we demonstrate the potential of EGCG for antimicrobial treatment and/or therapeutic adjuvant against antibiotic-resistant microorganisms and report divergent patterns of epigenetic modulators expression associated with phenotypic resistance profiles.
- Epigenetic and Drug Response Modulation of Epigalocaten-In-3-Gallate in Staphylococcus aureus with Divergent Resistance PhenotypesPublication . Mira, AR; Zeferino, AS; Inácio, R; Delgadinho, M; Brito, M; Calado, CRC.; Ribeiro, EHealthcare-associated methicillin-resistant Staphylococcus aureus infections represent extremely high morbidity and mortality rates worldwide. We aimed to assess the antimicrobial potential and synergistic effect between Epigalocatenin-3-gallate (EGCG) and different antibiotics in S. aureus strains with divergent resistance phenotypes. EGCG exposure effects in epigenetic and drug resistance key modulators were also evaluated. S. aureus strains (n = 32) were isolated from infected patients in a Lisbon hospital. The identification of the S. aureus resistance phenotype was performed through automatized methods. The antibiotic synergistic assay was performed through disk diffusion according to EUCAST guidelines with co-exposure to EGCG (250, 100, 50 and 25 µg/mL). The bacteria's molecular profile was assessed through FTIR spectroscopy. The transcriptional expression of OrfX, SpdC and WalKR was performed by using qRT-PCR. FTIR-spectroscopy analysis enabled the clear discrimination of MRSA/MSSA strains and the EGCG exposure effect in the bacteria's molecular profiles. Divergent resistant phenotypes were associated with divergent transcriptional expression of the epigenetic modulator OrfX, particularly in MRSA strains, as well as the key drug response modulators SpdC and WalKR. These results clearly demonstrate that EGCG exposure alters the expression patterns of key epigenetic and drug response genes with associated divergent-resistant profiles, which supports its potential for antimicrobial treatment and/or therapeutic adjuvant against antibiotic-resistant microorganisms.