Production and Characterization of Graphene Oxide Surfaces against Uropathogens

Graphene and its functionalized derivatives have been increasingly applied in the biomedi-cal field, particularly in the production of antimicrobial and anti-adhesive surfaces. This study aimed to evaluate the performance of graphene oxide (GO)/polydimethylsiloxane (PDMS) composites against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. GO/PDMS composites containing different GO loadings (1, 3, and 5 wt.%) were synthesized and characterized regarding their morphol-ogy, roughness, and hydrophobicity, and tested for their ability to inhibit biofilm formation under conditions that mimic urinary tract environments. Biofilm formation was assessed by determining the number of total and culturable cells. Additionally, the antibacterial mechanisms of action of GO were investigated for the tested uropathogens. Results indicated that the surfaces containing GO had greater roughness and increased hydrophobicity than PDMS. Biofilm analysis showed that the 1 wt.% GO/PDMS composite was the most effective in reducing S. aureus biofilm formation. In oppo-sition, P. aeruginosa biofilms were not inhibited by any of the synthesized composites. Furthermore, 1% (w/v) GO increased the membrane permeability, metabolic activity, and endogenous reactive oxygen species (ROS) synthesis in S. aureus. Altogether, these results suggest that GO/PDMS com-posites are promising materials for application in urinary catheters, although further investigation is required

Microglial Sirtuin 2 shapes long-term potentiation in hippocampal slices

Copyright © 2020 Sa de Almeida, Vargas, Fonseca-Gomes, Tanqueiro, Belo, Miranda-Lourenço, Sebastião, Diógenes and Pais. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Microglial cells have emerged as crucial players in synaptic plasticity during development and adulthood, and also in neurodegenerative and neuroinflammatory conditions. Here we found that decreased levels of Sirtuin 2 (Sirt2) deacetylase in microglia affects hippocampal synaptic plasticity under inflammatory conditions. The results show that long-term potentiation (LTP) magnitude recorded from hippocampal slices of wild type mice does not differ between those exposed to lipopolysaccharide (LPS), a pro-inflammatory stimulus, or BSA. However, LTP recorded from hippocampal slices of microglial-specific Sirt2 deficient (Sirt2-) mice was significantly impaired by LPS. Importantly, LTP values were restored by memantine, an antagonist of N-methyl-D-aspartate (NMDA) receptors. These results indicate that microglial Sirt2 prevents NMDA-mediated excitotoxicity in hippocampal slices in response to an inflammatory signal such as LPS. Overall, our data suggest a key-protective role for microglial Sirt2 in mnesic deficits associated with neuroinflammation.This study was supported by Santa Casa da Misericórdia de Lisboa (MB37-2017), GAPIC Research Program of the University of Lisbon Medical School (n° 2014002 and n° 2015028) and the following doctoral grants: PD/BD/128091/2016, SFRH/BD/118238/2016, PD/BD/114337/2016, and PD/BD/1144- 41/2016.info:eu-repo/semantics/publishedVersio

The Neuroprotective Action of Amidated-Kyotorphin on Amyloid β Peptide-Induced Alzheimer’s Disease Pathophysiology

Kyotorphin (KTP, l-tyrosyl-l-arginine) is an endogenous dipeptide initially described to have analgesic properties. Recently, KTP was suggested to be an endogenous neuroprotective agent, namely for Alzheimer’s disease (AD). In fact, KTP levels were shown to be decreased in the cerebrospinal fluid of patients with AD, and recent data showed that intracerebroventricular (i.c.v.) injection of KTP ameliorates memory impairments in a sporadic rat model of AD. However, this administration route is far from being a suitable therapeutic strategy. Here, we evaluated if the blood-brain permeant KTP-derivative, KTP-NH2, when systemically administered, would be effective in preventing memory deficits in a sporadic AD animal model and if so, which would be the synaptic correlates of that action. The sporadic AD model was induced in male Wistar rats through i.c.v. injection of amyloid β peptide (Aβ). Animals were treated for 20 days with KTP-NH2 (32.3 mg/kg, intraperitoneally (i.p.), starting at day 3 after Aβ administration) before memory testing (Novel object recognition (NOR) and Y-maze (YM) tests). Animals were then sacrificed, and markers for gliosis were assessed by immunohistochemistry and Western blot analysis. Synaptic correlates were assessed by evaluating theta-burst induced long term potentiation (LTP) of field excitatory synaptic potentials (fEPSPs) recorded from hippocampal slices and cortical spine density analysis. In the absence of KTP-NH2 treatment, Aβ-injected rats had clear memory deficits, as assessed through NOR or YM tests. Importantly, these memory deficits were absent in Aβ-injected rats that had been treated with KTP-NH2, which scored in memory tests as control (sham i.c.v. injected) rats. No signs of gliosis could be detected at the end of the treatment in any group of animals. LTP magnitude was significantly impaired in hippocampal slices that had been incubated with Aβ oligomers (200 nM) in the absence of KTP-NH2. Co-incubation with KTP-NH2 (50 nM) rescued LTP toward control values. Similarly, Aβ caused a significant decrease in spine density in cortical neuronal cultures, and this was prevented by co-incubation with KTP-NH2 (50 nM). In conclusion, the present data demonstrate that i.p. KTP-NH2 treatment counteracts Aβ-induced memory impairments in an AD sporadic model, possibly through the rescuing of synaptic plasticity mechanisms.publishersversionpublishe

Oocyte and ovarian tissue cryopreservation in European countries : statutory background, practice, storage and use

STUDY QUESTION: What is known in Europe about the practice of oocyte cryopreservation (OoC), in terms of current statutory background, funding conditions, indications (medical and ‘non-medical’) and specific number of cycles? SUMMARY ANSWER: Laws and conditions for OoC vary in Europe, with just over half the responding countries providing this for medical reasons with state funding, and none providing funding for ‘non-medical’ OoC. WHAT IS ALREADY KNOWN: The practice of OoC is a well-established and increasing practice in some European countries, but data gathering on storage is not homogeneous, and still sparse for use. Ovarian tissue cryopreservation (OtC) is only practiced and registered in a few countries. STUDY DESIGN, SIZE, AND DURATION: A transversal collaborative survey on OoC and OtC, was designed, based on a country questionnaire containing information on statutory or professional background and practice, as well as available data on ovarian cell and tissue collection, storage and use. It was performed between January and September 2015. PARTICIPANTS/MATERIALS, SETTING AND METHODS: All ESHRE European IVF Monitoring (EIM) consortium national coordinators were contacted, as well as members of the ESHRE committee of national representatives, and sent a questionnaire. The form included national policy and practice details, whether through current existing law or code of practice, criteria for freezing (age, health status), availability of funding and the presence of a specific register. The questionnaire also included data on both the number of OoC cycles and cryopreserved oocytes per year between 2010 and 2014, specifically for egg donation, fertility preservation for medical disease, ‘other medical’ reasons as part of an ART cycle, as well as for ‘non-medical reasons’ or age-related fertility decline. Another question concerning data on freezing and use of ovarian tissue over 5 years was added and sent after receiving the initial questionnaire. MAIN RESULTS AND THE ROLE OF CHANCE: Out of 34 EIM members, we received answers regarding OoC regulations and funding conditions from 27, whilst 17 countries had recorded data for OoC, and 12 for OtC. The specific statutory framework for OoC and OtC varies from absent to a strict frame. A total of 34 705 OoC cycles were reported during the 5-year-period, with a continuous increase. However, the accurate description of numbers was concentrated on the year 2013 because it was the most complete. In 2013, a total of 9126 aspirations involving OoC were reported from 16 countries. Among the 8885 oocyte aspirations with fully available data, the majority or 5323 cycles (59.9%) was performed for egg donation, resulting in the highest yield per cycle, with an average of 10.4 oocytes frozen per cycle. OoC indication was ‘serious disease’ such as cancer in 10.9% of cycles, other medical indications as ‘part of an ART cycle’ in 16.1%, and a non-medical reason in 13.1%. With regard to the use of OoC, the number of specifically recorded frozen oocyte replacement (FOR) cycles performed in 2013 for all medical reasons was 14 times higher than the FOR for non-medical reasons, using, respectively, 8.0 and 8.4 oocytes per cycle. Finally, 12 countries recorded storage following OtC and only 7 recorded the number of grafted frozen/thawed tissues. LIMITATIONS, REASONS FOR CAUTION: Not all countries have data regarding OoC collection, and some data came from voluntary collaborating centres, rather than a national authority or register. Furthermore, the data related to use of OoC were not included for two major players in the field, Italy and Spain, where numbers were conflated for medical and non-medical reasons. Finally, the number of cycles started with no retrieval is not available. Data are even sparser for OtC. WIDER IMPLICATIONS OF THE FINDINGS: There is a need for ART authorities and professional bodies to record precise data for practice and use of OoC (and OtC), according to indications and usage, in order to reliably inform all stakeholders including women about the efficiency of both methods. Furthermore, professional societies should establish professional standards for access to and use of OoC and OtC, and give appropriate guidance to all involved. STUDY FUNDING/COMPETING INTEREST(S): The study was supported by ESHRE. There are no conflicts of interest.peer-reviewe

High-caloric diet Induces memory impairment and disrupts synaptic plasticity in aged rats

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).The increasing consumption of sugar and fat seen over the last decades and the consequent overweight and obesity, were recently linked with a deleterious effect on cognition and synaptic function. A major question, which remains to be clarified, is whether obesity in the elderly is an additional risk factor for cognitive impairment. We aimed at unravelling the impact of a chronic high caloric diet (HCD) on memory performance and synaptic plasticity in aged rats. Male rats were kept on an HCD or a standard diet (control) from 1 to 24 months of age. The results showed that under an HCD, aged rats were obese and displayed significant long-term recognition memory impairment when compared to age-matched controls. Ex vivo synaptic plasticity recorded from hippocampal slices from HCD-fed aged rats revealed a reduction in the magnitude of long-term potentiation, accompanied by a decrease in the levels of the brain-derived neurotrophic factor receptors TrkB full-length (TrkB-FL). No alterations in neurogenesis were observed, as quantified by the density of immature doublecortin-positive neurons in the hippocampal dentate gyrus. This study highlights that obesity induced by a chronic HCD exacerbates age-associated cognitive decline, likely due to impaired synaptic plasticity, which might be associated with deficits in TrkB-FL signaling.This research was funded by Santa Casa da Misericórdia de Lisboa—MB37-2017; Fundação para a Ciência e a Tecnologia (FCT)—IF/01227/2015; and it received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952455. Researchers were supported by the following: S.L.P.—FCT (PD/BD/150341/2019); C.M.-L.—FCT (SFRH/BD/118238/2016) and Universidade de Lisboa (BD2015); R.F.B.—FCT (PD/BD/114337/2016); R.S.R.—FCT (SFRH/BD/129710/2017); S.R.T.—FCT (SFRH/BD/128091/2016).info:eu-repo/semantics/publishedVersio

S327 phosphorylation of the presynaptic protein SEPTIN5 increases in the early stages of neurofibrillary pathology and alters the functionality of SEPTIN5

© 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)Alzheimer's disease (AD) is the most common form of dementia, which is neuropathologically characterized by extracellular senile plaques containing amyloid-β and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein. Previous studies have suggested a role for septin (SEPTIN) protein family members in AD-associated cellular processes. Here, we elucidated the potential role of presynaptic SEPTIN5 protein and its post-translational modifications in the molecular pathogenesis of AD. RNA and protein levels of SEPTIN5 showed a significant decrease in human temporal cortex in relation to the increasing degree of AD-related neurofibrillary pathology. Conversely, an increase in the phosphorylation of the functionally relevant SEPTIN5 phosphorylation site S327 was observed already in the early phases of AD-related neurofibrillary pathology, but not in the cerebrospinal fluid of individuals fulfilling the criteria for mild cognitive impairment due to AD. According to the mechanistic assessments, a link between SEPTIN5 S327 phosphorylation status and the effects of SEPTIN5 on amyloid precursor protein processing and markers of autophagy was discovered in mouse primary cortical neurons transduced with lentiviral constructs encoding wild type SEPTIN5 or SEPTIN5 phosphomutants (S327A and S327D). C57BL/6 J mice intrahippocampally injected with lentiviral wild type SEPTIN5 or phosphomutant constructs did not show changes in cognitive performance after five to six weeks from the start of injections. However, SEPTIN5 S327 phosphorylation status was linked to changes in short-term synaptic plasticity ex vivo at the CA3-CA1 synapse. Collectively, these data suggest that SEPTIN5 and its S327 phosphorylation status play a pivotal role in several cellular processes relevant for AD.This work was supported by the Academy of Finland (grant numbers 307866, 330178 and 315459); Sigrid Jusélius Foundation; the Strategic Neuroscience Funding of the University of Eastern Finland; Fundação para a Ciência e Tecnologia (grant numbers PD/BD/128390/2017, SFRH/BD/118238/2016, PD/BD/114441/2016, PD/BD/128091/2016, PD/BD/114337/2016, and PTDC/MED-NEU/27946/2017); Santa Casa da Misericórdia de Lisboa (grant number MB-37-2017); SynaNet (LISBOA-01-0145-FEDER-0073919 under the grant agreement no. 692340).info:eu-repo/semantics/publishedVersio

Challenges of BDNF-based therapies : from common to rare diseases

© 2020 Elsevier Ltd. All rights reserved.Neurotrophins are a well-known family of neurotrophic factors that play an important role both in the central and peripheral nervous systems, where they modulate neuronal survival, development, function and plasticity. Brain-derived neurotrophic factor (BDNF) possesses diverse biological functions which are mediated by the activation of two main classes of receptors, the tropomyosin-related kinase (Trk) B and the p75 neurotrophin receptor (p75NTR). The therapeutic potential of BDNF has drawn attention since dysregulation of its signalling cascades has been suggested to underlie the pathogenesis of both common and rare diseases. Multiple strategies targeting this neurotrophin have been tested; most have found obstacles that ultimately hampered their effectiveness. This review focuses on the involvement of BDNF and its receptors in the pathophysiology of Alzheimer's disease (AD), Amyotrophic Lateral Sclerosis (ALS) and Rett Syndrome (RTT). We describe the known mechanisms leading to the impairment of BDNF/TrkB signalling in these disorders. Such mechanistic insight highlights how BDNF signalling compromise can take various shapes, nearly disease-specific. Therefore, BDNF-based therapeutic strategies must be specifically tailored and are more likely to succeed if a combination of resources is employed.The work was supported by Fundação Calouste Gulbenkian and FMUL (grant awarded to T.M.R., 20130002/PEC/BG); Santa Casa da Misericórdia de Lisboa (MB37-2017); Fundação para a Ciência e Tecnologia (FCT, AdoRett – LISBOA-01- 0145-FEDER-031929/2017); Uni-versidade de Lisboa (grant awarded to C.M.L., BD2015); the Association Française du Syndrome de Rett; Program “Educaç ̃ao pela Ciˆencia” Bolsas CHLN/FMUL – GAPIC (Project No. 20190017); Twinning action (Syn-aNet) from the EU H2020 Programme; H2020-WIDESPREAD-05-2017- Twinning (EpiEpinet) (grant agreement No. 952455); and FCT/Minis-t ́erio da Ciˆencia, Tecnologia e Ensino Superior (MCTES), through the Fundos do Orçamento de Estado (UID/BIM/50005/2019). This work was supported by Fundaç ̃ao para a Ciˆencia e a Tecnologia (FCT), Lisboa, Portugal [Fellowship numbers: C.M.L (SFRH/BD/118238/2016), L.R.R (PD/BD/150344/2019), J.F.G (PD/BD/114441/2016), S.R.T (PD/BD/ 128091/2016), R.F.B (PD/BD/114337/2016), C.B.F (PD/BD/128390/ 2017), N.R (PD/BD/113463/2015info:eu-repo/semantics/publishedVersio