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How does high-fat diet disturb neuroregeneration? Clues for the role of miR-21 in the brain
Publication . Pires, Bruna Martins; Solá, Susana; Caldas, Margarida
The brain is one of the most metabolically active organs in the body. As such, many neurological diseases result from bioenergetic impairments, as observed in obesity. Mitochondrial and lipid metabolism strongly impact neural stem cell (NSC) activity and cognitive processes in the mature brain. New evidence suggests that microRNA-21 (miR-21) is upregulated in the liver of overweight mice and its ablation ameliorates obesity and associated metabolic disorders. Here, we aimed to identify whether obesity and miR-21-associated systemic alterations disrupt brain bioenergetics and NSC activity. For that, miR-21 whole-body knockout (KO), mir-21 liver KO and wild-type (WT) mice were fed a standard or high-fat diet (HFD) for 20 weeks. Brain tissues were characterized for molecular markers of mitochondrial function, neurogenesis, and lipid metabolism. Results showed that protein levels of NeuN, a marker for mature neurons, increase in HFD-fed WT mice by a mechanism independent of miR 21. Obese mice also showed changes in mitochondrial biogenesis markers TFAM and PGC-1α, which were abrogated in miR-21 KOs. Moreover, SREBP and LCAD, markers of lipogenesis and lipid degradation, respectively, were found deregulated in obese mice and rescued with miR 21 whole-body KO. Interestingly, the PDHE1 protein, a key subunit of pyruvate dehydrogenase involved in glucose metabolism, was decreased in this context, possibly indicating a metabolic switch. Curiously, the shrinkage of the neurogenic niches found in obese mice was rescued by both miR-21 KOs. Although obesity could increase the levels of immature neurons, potentiated in HFD miR-21 liver KO mice, it also triggered a dysfunctional migratory route. Finally, in vitro assays showed that an unsaturated lipid promotes proliferation and neuronal differentiation of NSCs, while a saturated one disrupts neurogenesis. Our findings provide new insights into the impact of an HFD on the adult brain, unraveling miR-21 as a potential pharmacological target to mitigate the influence of obesity in the brain.
Exploring triazene derivative's antimicrobial activity and its incorporation onto 3D-printed coatings
Publication . Vieira, Pedro Miguel Ascenso; Bettencourt, Ana F.; Panteli, Efthymia; Santos, Catarina; Gonçalves, Lídia M.; Francisco, Ana P.; Ribeiro, Isabel A.C.; Faculdade de Ciências e Tecnologia (FCT); Elsevier
Antimicrobial resistance has emerged as a significant health concern demanding the urgent development of new active molecules. Furthermore, within healthcare settings, medical devices can be the cause of microorganisms’ proliferation leading to infection. Thus, nowadays the need for novel antimicrobial biomaterials is mandatory. In this work different 1,3-diaryltriazenes were synthesized for incorporation as antimicrobials onto 3D-printed hydrogel coatings for polydimethylsiloxane (PDMS) substrates used in the production of different medical devices. Symmetric and asymmetric aryltriazenes were synthesized and characterized by spectroscopic methods. Antimicrobial activity was screened and the most active triazene was selected to be incorporated into the 3D-printed coatings that were further characterized by contact angle measurements, FTIR-ATR, SEM, drug release, antimicrobial activity, and cytocompatibility. The 1,3-bis (4-nitro-2-(trifluoromethyl)phenyl) triazene showed activity against Staphylococcus aureus with a minimum inhibitory concentration of 1 μg/mL and revealed no cytotoxicity towards HaCat cells. 3D-printed hydrogel coatings (comprising chitosan/starch and sodium alginate) loaded triazene were successfully produced for PDMS substrates. Triazene coatings presented high wettability and smoothness and revealed antimicrobial and antibiofilm activity (i.e., 96 % reduction) towards S. aureus. Additionally, the produced coatings showed no cytotoxicity under the tested conditions. This study marks the initial proof that incorporating triazenes into 3D-printed hydrogel-based coatings can diminish biofilm formation on widely used biomaterials, such as PDMS surfaces. Herein achieved outcomes have allowed us to confirm and propose a novel type of hybrid construct as an antimicrobial hydrogel coating.
Gold nanoparticles for photothermal therapy – Influence of experimental conditions on the properties of resulting AuNPs
Publication . Amaral, Mariana Neves; Nunes, Daniela; Fortunato, Elvira; Martins, Rodrigo; Rodrigues, Carla; Faísca, Pedro; Ferreira, Hugo Alexandre; Coelho, João M.P.; Gaspar, M. Manuela; Reis, Catarina Pinto; Faculdade de Ciências e Tecnologia (FCT); DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DQ - Departamento de Química; CQFB-REQUIMTE - Centro de Química Fina e Biotecnologia (Lab. Associado REQUIMTE); Editions de Sante
Gold nanoparticles (AuNPs)-mediated Photothermal Therapy (PTT) is a minimally-invasive therapeutic approach that uses AuNPs to convert light into heat, leading to the thermal ablation of tumors. Thus, the efficacy of this strategy strongly relies on the photothermal conversion potential of AuNPs. The ability to convert light into heat can be enhanced by tuning the physicochemical and optical properties of AuNPs. This can be achieved by changing the conditions of AuNP's synthesis, such as the order of addition of reagents. The present work entails to explore how varying the order of reagents addition modulates the properties of AuNPs, particularly enhancing the photothermal conversion potential of the resulting AuNPs and consequently, improving PTT efficacy. For this, eleven different AuNPs' nanoformulations were synthetized following different sequences of addition of reagents. These nanoformulations were characterized regarding their physicochemical properties namely size, surface charge, gold concentration, surface morphology and maximum absorbance wavelength. In addition, their thermal activation profiles were determined in vitro. Furthermore, the biocompatibility of different nanoformulations was also assessed. Three nanoformulations, with the most favorable photothermal activation profiles (AuNPs 2, 3 and 7), were then selected for preliminary in vitro safety and efficacy assays using a panel of cell lines. These three nanoformulations were deemed safe in vitro at the tested concentrations. At 250 μM of gold content, and after an incubation period of 4 h, followed by 5 min irradiation with a laser emitting at 808 nm (7.96 W/cm2), AuNPs 7 significantly reduced the cell viability of all cancer cell lines tested (MCF-7, HCT-116 and A375) by ≥ 45 %. However, such cytotoxic effect was not observed for the human keratinocyte cell line (HaCat), thus demonstrating its specificity towards cancer cells. Overall, the results herein presented reinforce that the order of reagents addition is highly important for achieving adequate AuNPs for PTT.
Design and evolution of a synthetic small protein scaffold based on the WW domain
Publication . Dias, Ana Margarida Gonçalves Carvalho; Teixeira, Gonçalo Duarte Gomes; Barbosa, Arménio Jorge Moura; Goncalves, Joao; Iranzo, Olga; Roque, Ana Cecília Afonso; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; Wiley-Blackwell
Protein engineering is a powerful tool in biotechnology and the basis to create unprecedented sequences, structures, and functions. The WW domains are a family of naturally occurring proteins involved in the molecular recognition of proline-rich and phosphorylated peptide sequences with relevance in cellular processes involved in human diseases. Due to their small size, WW domains represent appealing small protein domains for protein engineering and to generate novel functions as binders to non-cognate targets. Here, we designed a synthetic protein scaffold library based on the WW prototype sequence in which the loops were extended and randomized while maintaining structural stability. Using in vitro evolution by phage display against human serum albumin (HSA), we found a lead candidate that was produced by biological and chemical means and further characterized using experimental and computational tools. As a potential application for the lead binder, it was immobilized on a matrix and used to capture the target HSA. Overall, this work shows the versatility of WW domains as peptide scaffolds amenable for in vitro evolution against non-cognate targets.
Determination of mometasone furoate solubility, using deep eutectic systems, and topical formulation- experimental and computational studies
Publication . Craveiro, Rita; Rocha, Ângelo; Fernandes, Cláudio; Duarte, Ana Rita C.; Marto, Joana; Paiva, Alexandre; LAQV@REQUIMTE; Faculdade de Ciências e Tecnologia (FCT); DQ - Departamento de Química; Elsevier BV
The low solubility of some drugs in aqueous medium, is currently a challenge for the pharmaceutical industry, affecting drug bioavailability and treatment efficacy, so there is the need to find new solutions for this challenge. In this work, the solubility of a glucocorticoid drug, mometasone furoate (MF), in different deep eutectic systems (DES) is studied. DES present the advantage of being sustainable solvents, which can be used directly in the final formulation, and establish a synergistic effect with the drug. The solubility of MF in different DES is increased, when compared to the solubility of this drug in an aqueous medium, particularly in DES composed by levulinic acid and terpenes such as menthol and thymol, where the solubility of MF was of 24.1 and 103.3 mgMF/gDES, respectively. Solubility was also assessed using the computational determination of the Hansen solubility parameters of MF in these DES, in particular the total solubility parameter (δT) and Relative Energy Difference (RED). The obtained results correlate well with the MF measured experimentally, showing that this computational tool can be further used to predict MF solubility in DES. Furthermore, oil-in-water emulsions containing DES with MF were developed, allowing more versatility compared to the drug in powdered form, and were prepared containing 1 and 5 % of DES with MF. This work highlights that DES can have an important role in drug solubilization and in the development of new formulation strategies for the pharmaceutical industries.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso de avaliação no âmbito do Programa Plurianual de Financiamento de Unidades de I&D (2017/2018) - Financiamento Base
Número da atribuição
UIDB/04138/2020