Browsing by Author "Pereira, Ana Cláudia"
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- Cutibacterium acnes dysbiosis: Alternative therapeutics for clinical applicationPublication . Sá, Sara; Fernandes, Ruben; Gestoso, Álvaro; Macedo, José Mário; Martins-Mendes, Daniela; Pereira, Ana Cláudia; Baylina, PilarCutibacterium acnes (C. acnes) is a Gram-positive anaerobic facultative bacterium that is part of the human skin commensal microbiome. It colonizes various regions of the body, including the face, back, and chest. While typically a harmless commensal, under certain conditions, C. acnes can become pathogenic, leading to or promoting conditions such as acne vulgaris (AV), post-surgical infections, prostate cancer, and sarcoidosis. Current treatments for C. acnes infections often involve antibiotics, but the rise of antibiotic resistance has raised concerns. This review presents the virulence factors, clinical relevance, and current treatments of C. acnes, highlighting its association with AV, postsurgical infections, and other diseases. It also explores alternative innovative therapies such as phage therapy in development/research that are gaining prominence, with a growing focus on personalized medical approaches. To enhance C. acnes treatment while minimizing side effects and antibiotic prescription concerns, numerous clinical studies have been undertaken. These investigations span various pathological profiles and employ diverse strategies, such as utilizing bacterial extracts and compounds to restore healthy skin flora. The limitations and challenges of current and innovative treatments are also addressed, emphasizing the need for multidisciplinary strategies to combat C. acnes infections effectively.
- Effect of oxidative stress upon absorption of glucose by the human placenta: in vitro studies with BeWo cellsPublication . Pereira, Ana Cláudia; Martel, Fátima; Prudêncio, Cristina; Keating, ElisaPregnancy is a dynamic state and the placenta is a temporary organ that, among other important functions, plays a crucial role in the transport of nutrients and metabolites between the mother and the fetus, which is essential for a successful pregnancy. Among these nutrients, glucose is considered a primary source of energy and, therefore, fundamental to insure proper fetus development. Several studies have shown that glucose uptake is dependent on several morphological and biochemical placental conditions. Oxidative stress results from the unbalance between reactive oxygen species (ROS) and antioxidants, in favor of the first. During pregnancy, ROS, and therefore oxidative stress, increase, due to increased tissue oxygenation. Moreover, the relation between ROS and some pathological conditions during pregnancy has been well established. For these reasons, it becomes essential to understand if oxidative stress can compromise the uptake of glucose by the placenta. To make this study possible, a trophoblastic cell line, the BeWo cell line, was used. Experiments regarding glucose uptake, either under normal or oxidative stress conditions, were conducted using tert-butylhydroperoxide (tBOOH) as an oxidative stress inducer, and 3H-2-deoxy-D-glucose (3H-DG) as a glucose analogue. Afterwards, studies regarding the involvement of glucose facilitative transporters (GLUT) and the phosphatidylinositol 3-kinases (PI3K) and protein kinase C (PKC) pathways were conducted, also under normal and oxidative stress conditions. A few antioxidants, endogenous and from diet, were also tested in order to study their possible reversible effect of the oxidative effect of tBOOH upon apical 3H-DG uptake. Finally, transepithelial studies gave interesting insights regarding the apical-to-basolateral transport of 3H-DG. Results showed that 3H-DG uptake, in BeWo cells, is roughly 50% GLUT-mediated and that tBOOH (100 μM; 24h) decreases apical 3H-DG uptake in BeWo cells by about 33%, by reducing both GLUT- (by 28%) and non-GLUT-mediated (by 40%) 3H-DG uptake. Uptake of 3H-DG and the effect of tBOOH upon 3H-DG uptake are not dependent on PKC and PI3K. Moreover, the effect of tBOOH is not associated with a reduction in GLUT1 mRNA levels. Resveratrol, quercetin and epigallocatechin-3-gallate, at 50 μM, reversed, by at least 45%, the effect of tBOOH upon 3H-DG uptake. Transwell studies show that the apical-to-basolateral transepithelial transport of 3H-DG is increased by tBOOH.In conclusion, our results show that tBOOH caused a marked decrease in both GLUT and non-GLUT-mediated apical uptake of 3H-DG by BeWo cells. Given the association of increased oxidative stress levels with several important pregnancy pathologies, and the important role of glucose for fetal development, the results of this study appear very interesting.
- Enhanced 3T3-L1 differentiation into adipocytes by pioglitazone pharmacological activation of peroxisome proliferator activated receptor-gamma (PPAR-gamma)Publication . Teixeira, Catarina; Sousa, André P.; Santos, Inês; Rocha, Ana Catarina; Alencastre, Inês; Pereira, Ana Cláudia; Martins-Mendes, Daniela; Barata, Pedro; Baylina, Pilar; Fernandes, RúbenDespite the primary function of pioglitazone in antidiabetic treatment, this drug is a potent inducer of PPAR-γ, a crucial receptor that is involved in adipocyte differentiation. In this work, we propose an optimized methodology to enhance the differentiation of 3T3-L1 fibroblasts into adipocytes. This process is crucial for adipocyte secretome release, which is fundamental for understanding the molecular mechanisms that are involved in obesity for in vitro studies. To achieve this, a pioglitazone dose-response assay was determined over a range varying from 0 to 10 µM. Lipid accumulation was evaluated using Oil-Red-O. The results showed that 10 µM pioglitazone enhanced differentiation and increased secretome production. This secretome was then added into two cell lines: PC3 and RAW264.7. In the PC3 cells, an increase of aggressiveness was observed in terms of viability and proliferation, with the increase of anti-inflammatory cytokines. Conversely, in RAW264.7 cells, a reduction of viability and proliferation was observed, with a decrease in the overexpression of pro-inflammatory cytokines. Overall, the present work constitutes an improved method for adipocyte secretome production that is suitable for experimental biology studies and that could help with our understanding of the molecular mechanisms underlying adiposity influence in other cells.
- Enhanced role of PPARg with the Pro12Ala polymorphismPublication . Fernandes, Rúben; Pereira, Ana Cláudia; Oliveira, Rosa; Prudêncio, CristinaObesity and type 2 diabetes mellitus (T2D) are two major public health problems that have motivated the scientific community to investigate the high contribution of genetic factors to these disorders. The peroxisome proliferator activated by gamma 2 (PPARg2) plays an important role in the lipid metabolism. Since PPARg2 is expressed mainly in adipose tissue, a moderate reduction of its activity influences the sensitivity to insulin, diabetes, and other metabolic parameters. The present study aims to contribute to the elucidation of the impact of the Pro12Ala polymorphism associated with T2D and obesity through a meta-analysis study of the literature that included approximately 11500 individuals, from which 3870 were obese and 7625 were diabetic. Statistical evidence supports protective effect in T2D of polymorphism Pro12Ala of PPARg2 (OR = 0.702 with 95% CI: 0.622; 0.791, P <0.01). Conversely the same polymorphism Pro12Ala of PPARg2 seems to favor obesity since 1.196 more chance than non obese was found (OR=1.196 with 95% CI: 1.009; 1.417, P < 0.004). Our results suggest that Pro12Ala polymorphism enhances both adipogenic and antidiabetogenic physiological role of PPARg. Does Pro12Ala polymorphism represent an evolutionary step towards the stabilization of the molecular function of PPARg transcription factor signaling pathway?
- Exploring the potential protective effect of probiotics in obesity-induced colorectal cancer: What insights can in vitro models provide?Publication . Viana, Rejane; Rocha, Ana C.; Sousa, André P.; Ferreira, Diogo; Fernandes, Rúben; Almeida, Cátia; Pais, Patrick J.; Baylina, Pilar; Pereira, Ana CláudiaColorectal cancer (CRC) is the third most common cancer diagnosed today and the third leading cause of death among cancer types. CRC is one of the gastrointestinal tumors with obesity as the main extrinsic risk factor, since, according to authors, the meta-inflammation sustained by the excess adipose tissue can provide abundant circulating lipids, as well as hormones and metabolites crucial to tumor development and aggressiveness. The gut microbiota can protect the colon from metainflammation and endocrine changes caused by obesity. The present study aimed to investigate the antitumor activity of a commercial probiotic in intestinal tumor cells under two adiposity conditions. Experimental assays were performed on the Caco2 cell line (colon adenocarcinoma) supplemented with differentiated adipocyte’s secretomes of the 3T3-L1 cell line (mouse pre-adipocytes) in two adiposity conditions: (i) differentiation without the use of Pioglitazone (noPGZ) and (ii) differentiation using Pioglitazone (PGZ). The Caco2 cells were first exposed to both secretomes for 24 h and evaluated and subsequently exposed to probiotic extract followed by secretome and evaluated. The effects of these treatments were evaluated using cytotoxicity assays by MTT, cell migration by injury, and antioxidant activity by glutathione assay. The use of secretomes showed a statistically significant increase in cell viability in Caco2 cells, either in noPGZ (p < 0.01) or PGZ (p < 0.05), and the probiotic was not able to reduce this effect. In the injury assay, secretome increased cell migration by more than 199% in both adiposity conditions (p < 0.001 in noPGZ and p < 0.01 in PGZ). In the probiotic treatment, there was a reduction in cell migration compared to the control in adiposity conditions. The antioxidant response of Caco2 cells was increased in both adiposity conditions previously exposed to the probiotic supernatant. This pilot work brings to light some findings that may answer why the modulation of the intestinal microbiota using probiotics is an alternative strategy leading to improvements in the condition and stage of the colon tumor. Additional studies are needed to clarify the role of Pioglitazone in this type of tumor and the metabolites of obesity that are attenuated by the use of probiotics.
- GLP-1R and IL-6 expression in the gastrointestinal tract of a murine model of metabolic syndromePublication . Costa, José; Oliveira, Sofia; Pereira, Ana Cláudia; Soares, Raquel; Baylina, Pilar; Guerreiro, Susana G.; Fernandes, Rúben; Luís, CarlaGlucose homeostasis is a critical cornerstone in both health and disease. It is described to be regulated by the balance of insulin and glucagon secretion but, this bi-hormonal perspective is long overdue, since glucose homeostasis is now known to be a multi-hormonal process. Metabolic syndrome (MetS) is a cluster of metabolic features which includes impaired glucose metabolism and obesity. Obesity promotes a low chronic inflammation state due to release of bioactive molecules like cytokines, ultimately contributing to cardiovascular disease, diabetes and cancer. The gastrointestinal tract (GIT), namely stomach and intestine, has a vital role not only in the food uptake and absorption, but also in the production of incretin hormones, such as GLP-1. We aim to evaluate the GLP-1 receptor (GLP-1R) in the GIT of a MetS animal model, and to assess whether it correlates with inflammatory levels. The expression of GLP-1R and Interleukin-6 (IL-6) was evaluated in the stomach and intestine of mice subjected to Normal Diet (ND) and High Fat Diet (HFD) by immunohistochemistry. We observed that HFD fed animals presented lower levels of GLP-1R in stomach and intestine when compared with animals fed with ND. Concomitantly, these mice expressed increased levels of IL-6. GLP-1R expression is inversely correlated with the expression of the proinflammatory cytokine IL-6.
- Harvesting the power of green synthesis: gold nanoparticles tailored for prostate cancer therapyPublication . Oliveira, Marco; Sousa, André; Sá, Sara; Soares, Sílvia; Pereira, Ana Cláudia; Rocha, Ana Catarina; Pais, Patrick; Ferreira, Diogo; Almeida, Cátia; Luís, Carla; Lima, Cláudio; Almeida, Fábio; Gestoso, Álvaro; Duarte, Miguel-Correa; Barata, Pedro; Martins-Mendes, Daniela; Baylina, Pilar; Pereira, Carla F.; Fernandes, RúbenBiosynthetic gold nanoparticles (bAuNPs) present a promising avenue for enhancing biocompatibility and offering an economically and environmentally responsible alternative to traditional production methods, achieved through a reduction in the use of hazardous chemicals. While the potential of bAuNPs as anticancer agents has been explored, there is a limited body of research focusing on the crucial physicochemical conditions influencing bAuNP production. In this study, we aim to identify the optimal growth phase of Pseudomonas aeruginosa cultures that maximizes the redox potential and coordinates the formation of bAuNPs with increased efficiency. The investigation employs 2,6-dichlorophenolindophenol (DCIP) as a redox indicator. Simultaneously, we explore the impact of temperature, pH, and incubation duration on the biosynthesis of bAuNPs, with a specific emphasis on their potential application as antitumor agents. Characterization of the resulting bAuNPs is conducted using ATR-FT-IR, TEM, and UV-Vis spectroscopy. To gain insights into the anticancer potential of bAuNPs, an experimental model is employed, utilizing both non-neoplastic (HPEpiC) and neoplastic (PC3) epithelial cell lines. Notably, P. aeruginosa cultures at 9 h/OD600 = 1, combined with biosynthesis at pH 9.0 for 24 h at 58 ◦C, produce bAuNPs that exhibit smaller, more spherical, and less aggregated characteristics. Crucially, these nanoparticles demonstrate negligible effects on HPEpiC cells while significantly impacting PC3 cells, resulting in reduced viability, migration, and lower IL-6 levels. This research lays the groundwork for the development of more specialized, economical, and ecologically friendly treatment modalities.
- Moving towards personalized medicine—The broad use of aptamers for targeted theranosticPublication . Sousa, André P.; Rocha, Ana C.; Almeida, Cátia; Carneiro, Mariana C. C. G.; Pais, Patrick P.; Viana, Rejane; Fernandes, Rúben; Barata, Pedro; Gestoso, Álvaro; Ramalho, Susana; Martins-Mendes, Daniela; Baylina, Pilar; Pereira, Ana CláudiaAptamers are short, single-stranded oligonucleotides synthesized in vitro from a randomized oligonucleotide library against a specific target. These molecules are capable of binding to a wide range of biological targets with high specificity and affinity. They present great advantages over antibodies with potential applications in research, diagnosis, and therapeutics. Specifically for tumors with late-stage identification and poor prognosis, like pancreatic cancer, the study of novel aptamers holds tremendous potential for cancer diagnosis and treatment. Along with cancer treatment, aptamers have also shown high potential in regulating the immune response and modulating several critical steps of signaling cascades, such as in immune checkpoints. In the context of microbiota and infection, aptamers are being studied to identify microbes and their metabolites. This assessment has the potential to improve the detection and management of infectious diseases while assisting us in better understanding health risks and treatment outcomes by tracking changes in the microbiota. In this review, the potential of aptamers is explored regarding their applications in cancer, immune, and microbiota therapy.
- New Quantum-Dot-Based Fluorescent Immunosensor for Cancer Biomarker DetectionPublication . Sousa, Mariana P.; Piloto, Ana Margarida L.; Pereira, Ana Cláudia; Schmitt, Fernando; Fernandes, Ruben; Moreira, Felismina T. C.Cancer antigen 15-3 (CA 15-3) is a biomarker for breast cancer used to monitor response to treatments and disease recurrence. The present work demonstrates the preparation and application of a fluorescent biosensor for ultrasensitive detection of the cancer antigen CA 15-3 protein tumor marker using mercaptopropionic-acid-functionalized cadmium telluride (CdTe@MPA) quantum dots (QDs) conjugated with CA 15-3 antibodies. First, the QDs were synthesized by the hydrothermal route, resulting in spherical nanoparticles up to 3.50 nm in diameter. Subsequently, the QD conjugates were characterized by Fourier transform infrared spectroscopy (FTIR), UV absorption, and fluorescence. The interaction between the conjugates and the protein was studied by fluorescence spectroscopy in buffer and in 10-fold diluted commercial human serum. Calibration in spiked serum samples gave a detection limit of 0.027 U/mL, 1000-fold lower than the clinical limit for CA 15-3 (25 U/mL to 30 U/mL), indicating that this is an ultrasensitive technique. In addition, a rapid response was obtained within 10 min. The biosensor was selective in the presence of the interfering serum proteins BSA, CEA, and CA-125, with a maximum interference of 2% for BSA. The percent recovery was close to 100% with maximum relative standard deviation (RSD%) values of 1.56. Overall, the developed CA 15-3 biosensor provides a simple and sensitive method for ultrasensitive monitoring of breast cancer, as well as the ability to detect other molecules of interest in human serum matrices.
- Relação entre os hábitos alimentares e actividade física com o excesso de peso em adolescentes portuguesesPublication . Prudêncio, Cristina; Dores, Artemisa Rocha; Fernandes, Ruben; Peixoto, Vanda; Pereira, Ana Cláudia; Borges, CristinaA obesidade é uma patologia que tem aumentado drasticamente nos últimos anos, sendo que a mesma se tem manifestado de forma particularmente assustadora em crianças e adolescentes.