PT Government Associate Laboratory

Braga, Portugal

PT Government Associate Laboratory

Braga, Portugal
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Patricio P.,University of Minho | Patricio P.,PT Government Associate Laboratory | Mateus-Pinheiro A.,University of Minho | Mateus-Pinheiro A.,PT Government Associate Laboratory | And 4 more authors.
Molecular Neurobiology | Year: 2013

Since adult neurogenesis became a widely accepted phenomenon, much effort has been put in trying to understand the mechanisms involved in its regulation. In addition, the pathophysiology of several neuropsychiatric disorders, such as depression, has been associated with imbalances in adult hippocampal neurogenesis. These imbalances may ultimately reflect alterations at the cell cycle level, as a common mechanism through which intrinsic and extrinsic stimuli interact with the neurogenic niche properties. Thus, the comprehension of these regulatory mechanisms has become of major importance to disclose novel therapeutic targets. In this review, we first present a comprehensive view on the cell cycle components and mechanisms that were identified in the context of the homeostatic adult hippocampal neurogenic niche. Then, we focus on recent work regarding the cell cycle changes and signaling pathways that are responsible for the neurogenesis imbalances observed in neuropathological conditions, with a particular emphasis on depression. © 2013 The Author(s).

Soares C.A.,Columbia University | Soares C.A.,University of Minho | Soares C.A.,PT Government Associate Laboratory | Mason C.A.,Columbia University
Developmental Neurobiology | Year: 2015

During development of the mammalian eye, the first retinal ganglion cells (RGCs) that extend to the brain are located in the dorsocentral (DC) retina. These RGCs extend to either ipsilateral or contralateral targets, but the ipsilateral projections do not survive into postnatal periods. The function and means of disappearance of the transient ipsilateral projection are not known. We have followed the course of this transient early ipsilateral cohort of RGCs, paying attention to how far they extend, whether they enter targets and if so, which ones, and the time course of their disappearance. The DC ipsilateral RGC axons were traced using DiI labeling at E13.5 and E15.5 to compare the proportion of ipsi- versus contralateral projections during the first period of growth. In utero electroporation of E12.5 retina with GFP constructs was used to label axons that could be visualized at succeeding time points into postnatal ages. Our results show that the earliest ipsilateral axons grow along the cellular border of the brain, and are segregated from the laterally positioned contralateral axons from the same retinal origin. In agreement with previous reports, although many early RGCs extend ipsilaterally, after E16 their number rapidly declines. Nonetheless, some ipsilateral axons from the DC retina enter the superior colliculus and arborize minimally, but very few enter the dorsal lateral geniculate nucleus and those that do extend only short branches. While the mechanism of selective axonal disappearance remains elusive, these data give further insight into establishment of the visual pathways. © 2015 Wiley Periodicals, Inc.

Roque S.,University of Minho | Roque S.,PT Government Associate Laboratory | Mesquita A.R.,University of Minho | Palha J.A.,University of Minho | And 5 more authors.
Frontiers in Behavioral Neuroscience | Year: 2014

Maternal separation (MS), an early life stressful event, has been demonstrated to trigger neuropsychiatric disorders later in life, in particular depression. Experiments using rodents subjected to MS protocols have been very informative for the establishment of this association. However, the mechanism by which MS leads to neuropsychiatric disorders is far from being understood. This is probably associated with the multifactorial nature of depression but also with the fact that different research MS protocols have been used (that vary on temporal windows and time of exposure to MS). In the present study, MS was induced in rats in two developmental periods: for 6 h per day for 14 days between postnatal days 2-15 (MS2-15) and 7-20 (MS7-20). These two periods were defined to differ essentially on the almost complete (MS2-15) or partial (MS7-20) overlap with the stress hypo-responsive period. Behavioral, immunological, and endocrine parameters, frequently associated with depressive-like behavior, were analyzed in adulthood. Irrespectively from the temporal window, both MS exposure periods led to increased sera corticosterone levels. However, only MS2-15animals displayed depressive and anxious-like behaviors. Moreover, MS2-15was also the only group presenting alterations in the immune system, displaying decreased percentage of CD8+T cells, increased spleen T cell CD4/CD8 ratio, and thymocytes with increased resistance to dexamethasone-induced cell death. A linear regression model performed to predict depressive-like behavior showed that both corticosterone levels and T cell CD4/CD8 ratio explained 37% of the variance observed in depressive-like behavior. Overall, these findings highlight the existence of "critical periods" for early life stressful events to exert programing effects on both central and peripheral systems, which are of relevance for distinct patterns of susceptibility to emotional disorders later in life. © 2014 Roque,Mesquita, Palha, Sousa and Correia-Neves.

Nebenzahl-Guimaraes H.,Harvard University | Nebenzahl-Guimaraes H.,National Institute for Public Health and the Environment RIVM | Nebenzahl-Guimaraes H.,University of Minho | Nebenzahl-Guimaraes H.,PT Government Associate Laboratory | And 4 more authors.
Journal of Antimicrobial Chemotherapy | Year: 2014

Background: Improving our understanding of the relationship between the genotype and the drug resistance phenotype of Mycobacterium tuberculosis will aid the development of more accurate molecular diagnostics for drug-resistant tuberculosis. Studies that use direct genetic manipulation to identify the mutations that cause M. tuberculosis drug resistance are superior to associational studies in elucidating an individual mutation's contribution to the drug resistance phenotype. Methods: We systematically reviewed the literature for publications reporting allelic exchange experiments in any of the resistance-associated M. tuberculosis genes. We included studies that introduced single point mutations using specialized linkage transduction or site-directed/in vitro mutagenesis and documented a change in the resistance phenotype. Results: We summarize evidence supporting the causal relationship of 54 different mutations in eight genes (katG, inhA, kasA, embB, embC, rpoB, gyrA and gyrB) and one intergenic region (furA-katG) with resistance to isoniazid, the rifamycins, ethambutol and fluoroquinolones. We observed a significant role for the strain genomic background in modulating the resistance phenotype of 21 of these mutations and found examples of where the same drug resistance mutations caused varying levels of resistance to different members of the same drug class. Conclusions: This systematic review highlights those mutations that have been shown to causally change phenotypic resistance in M. tuberculosis and brings attention to a notable lack of allelic exchange data for several of the genes known to be associated with drug resistance. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.

Baptista M.S.,University of Minho | Baptista M.S.,PT Government Associate Laboratory | Duarte C.B.,University of Coimbra | Maciel P.,University of Minho | Maciel P.,PT Government Associate Laboratory
Cellular and Molecular Life Sciences | Year: 2012

In addition to its central roles in protein quality control, regulation of cell cycle, intracellular signaling, DNA damage response and transcription regulation, the ubiquitin- proteasome system (UPS) plays specific roles in the nervous system, where it contributes to precise connectivity through development, and later assures functionality by regulating a wide spectrum of neuron-specific cellular processes. Aberrations in this system have been implicated in the etiology of neurodevelopmental and neurodegenerative diseases. In this review, we provide an updated viewon the UPS and highlight recent findings concerning its role in normal and diseased nervous systems. We discuss the advantages of the model organism Caenorhabditis elegans as a tool to unravel the major unsolved questions concerning this biochemical pathway and its involvement in nervous system function and dysfunction, and expose the new possibilities, using state-of-the-art techniques, to assess UPS function using this model system. © 2012 Springer Basel AG.

Costa R.R.,University of Minho | Costa R.R.,PT Government Associate Laboratory | Custodio C.A.,University of Minho | Arias F.J.,University of Valladolid | And 4 more authors.
Small | Year: 2011

In this work, biomimetic smart thin coatings using chitosan and a recombinant elastin-like recombinamer (ELR) containing the cell attachment sequence arginine-glycine-(aspartic acid) (RGD) are fabricated through a layer-by-layer approach. The synthetic polymer is characterized for its molecular mass and composition using mass spectroscopy and peptide sequencing. The adsorption of each polymeric layer is followed in situ at room temperature and pH 5.5 using a quartz-crystal microbalance with dissipation monitoring, showing that both polymers can be successfully combined to conceive nanostructured, multilayered coatings. The smart properties of the coatings are tested for their wettability by contact angle (CA) measurements as a function of external stimuli, namely temperature, pH, and ionic strength. Wettability transitions are observed from a moderate hydrophobic surface (CAs approximately from 62° to 71°) to an extremely wettable one (CA considered as 0°) as the temperature, pH, and ionic strength are raised above 50 °C, 11, and 1.25 M, respectively. Atomic force microscopy is performed at pH 7.4 and pH 11 to assess the coating topography. In the latter, the results reveal the formation of large and compact structures upon the aggregation of ELRs at the surface, which increase water affinity. Cell adhesion tests are conducted using a SaOs-2 cell line. Enhanced cell adhesion is observed in the coatings, as compared to a coating with a chitosan-ending film and a scrambled arginine-(aspartic acid)-glycine (RDG) biopolymer. The results suggest that such films could be used in the future as smart biomimetic coatings of biomaterials for different biomedical applications, including those in tissue engineering or in controlled delivery systems. Nanostructured multilayered films of chitosan and an elastin-like recombinamer are constructed. The thin films are demonstrated to possess stimuli-responsive and cyclic wettability changes from moderately hydrophobic to superhydrophilic, accompanied by the formation of spherical "micelle-like" structures. The incorporation of arginine-glycine-aspartic acid (RGD) in the recombinamer sequence improved cell adhesion. These features make of this system a promising alternative to classical layer-by-layer films with smart nature and increased functionality. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cotter J.,Centro Hospitalar do Alto Ave | Cotter J.,University of Minho | Cotter J.,PT Government Associate Laboratory | Dias de Castro F.,Centro Hospitalar do Alto Ave | And 2 more authors.
Journal of Crohn's and Colitis | Year: 2014

Background and aims: Small bowel capsule endoscopy (SBCE) may detect proximal small bowel lesions that have been previously missed by ileocolonoscopy and small bowel imaging in patients with known ileal and/or colonic Crohn's disease (CD). We aimed to evaluate whether the therapeutic management is influenced by SBCE findings. Methods: Retrospective single center study. Inclusion of consecutive patients with known non-stricturing and non-penetrating ileal and/or colonic CD, submitted to SBCE to evaluate disease extension and activity, with ≥ 1. year follow-up. Lesions were classified with the Lewis score (LS) as non-significant (LS. <. 135), mild (135. ≤. LS. ≤. 790), or moderate-to-severe (LS. >. 790). Therapeutic changes were assessed three months after SBCE. Results: Fifty consecutive patients (35. ±. 13. years, 52% females) were included. At ileocolonoscopy, disease location was ileal (L1) in 60%, colonic (L2) in 10% and ileocolonic (L3) in 30% of the patients. In 33 patients (66%) SBCE detected significant proximal lesions previously missed by other modalities. The proportion of patients on thiopurines and/or biologics before SBCE was 2/50 (4%); this was significantly higher three months after SBCE, 15/50 (30%), p. = 0.023. Treatment with thiopurines and/or biologics was started more often in patients with proximal small bowel lesions [13/33 (39%) vs. 1/17 (6%), p. = 0.011, relative risk (RR) 6.5], particularly when severe (6%, 36% and 45% of patients with non-significant, mild and moderate-to-severe inflammation, respectively). Conclusions: SBCE diagnoses previously undetected lesions and it influences therapeutic management of CD, triggering an earlier introduction of immunomodulators and/or biological therapy. © 2014 European Crohn's and Colitis Organisation.

Bruchfeld J.,Karolinska University Hospital | Correia-Neves M.,University of Minho | Correia-Neves M.,PT Government Associate Laboratory | Kallenius G.,Karolinska Institutet
Cold Spring Harbor Perspectives in Medicine | Year: 2015

Tuberculosis (TB) and human immunodeficiency virus/acquired immunodeficiency syn-drome (HIV/AIDS) constitute the main burden of infectious disease in resource-limited countries. In the individual host, the two pathogens, Mycobacterium tuberculosis and HIV, potentiate one another, accelerating the deterioration of immunological functions. In high-burden settings, HIV coinfection is the most important risk factor for developing active TB, which increases the susceptibility to primary infection or reinfection and also the risk of TB reactivation for patients with latent TB. M. tuberculosis infection also has a negative impact on the immune response to HIV, accelerating the progression from HIV infection to AIDS. The clinical management of HIV-associated TB includes the integration of effective anti-TB treatment, use of concurrent antiretroviral therapy (ART), prevention of HIV-related comorbidities, management of drug cytotoxicity, and prevention/treatment of immune reconstitution inflammatory syndrome (IRIS). © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

Costa P.F.,European Institute of Excellence on Tissue Engineering and Regenerative Medicine | Costa P.F.,PT Government Associate Laboratory | Vaquette C.,Queensland University of Technology | Zhang Q.,University of Sichuan | And 4 more authors.
Journal of Clinical Periodontology | Year: 2014

Aim This study investigated the ability of an osteoconductive biphasic scaffold to simultaneously regenerate alveolar bone, periodontal ligament and cementum. Materials and Methods A biphasic scaffold was built by attaching a fused deposition modelled bone compartment to a melt electrospun periodontal compartment. The bone compartment was coated with a calcium phosphate (CaP) layer for increasing osteoconductivity, seeded with osteoblasts and cultured in vitro for 6 weeks. The resulting constructs were then complemented with the placement of PDL cell sheets on the periodontal compartment, attached to a dentin block and subcutaneously implanted into athymic rats for 8 weeks. Scanning electron microscopy, X-ray diffraction, alkaline phosphatase and DNA content quantification, confocal laser microscopy, micro computerized tomography and histological analysis were employed to evaluate the scaffold's performance. Results The in vitro study showed that alkaline phosphatase activity was significantly increased in the CaP-coated samples and they also displayed enhanced mineralization. In the in vivo study, significantly more bone formation was observed in the coated scaffolds. Histological analysis revealed that the large pore size of the periodontal compartment permitted vascularization of the cell sheets, and periodontal attachment was achieved at the dentin interface. Conclusions This work demonstrates that the combination of cell sheet technology together with an osteoconductive biphasic scaffold could be utilized to address the limitations of current periodontal regeneration techniques. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Luz G.M.,European Institute of Excellence on Tissue Engineering and Regenerative Medicine | Luz G.M.,PT Government Associate Laboratory | Mano J.F.,European Institute of Excellence on Tissue Engineering and Regenerative Medicine | Mano J.F.,PT Government Associate Laboratory
Nanotechnology | Year: 2011

Bioactive glass nanoparticles (BG-NPs), based on both ternary (SiO 2-CaO-P2O5) and binary (SiO2-CaO) systems, were prepared via an optimized sol-gel method. The pH of preparation and the effect of heat treatment temperature were evaluated, as well as the effect of suppressing P in the bioactivity ability of the materials. The morphology and composition of the BG-NPs were studied using FTIR, XRD and SEM. The bioactive character of these materials was accessed invitro by analyzing the ability for apatite formation onto the surface after being immersed in simulated body fluid (SBF). XRD, EDX and SEM were used to confirm the bioactivity of the materials. The BG-NP effect on cell metabolic activity was assessed by seeding L929 cells with their leachables, proving the non-cytotoxicity of the materials. Finally the most bioactive BG-NPs developed (ternary system prepared at pH11.5 and treated at 700 °C) were successfully combined with chitosan in the production of biomimetic nanocomposite osteoconductive membranes that could have the potential to be used in guided tissue regeneration. © IOP Publishing Ltd.

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