71 research outputs found

    Inorganic Coordination Chemistry: Where We Stand in Cancer Treatment?

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    Metals have unique characteristics such as variable coordination modes, redox activity, and reactivity being indispensable for several biochemical processes in cells. Due to their reactivity, their concentration is tightly regulated inside the cells, and abnormal concentrations are associated with many disorders, such as cancer. As such metal complexes turned out to be very attractive as potential anticancer agents. The discovery of cisplatin was a crucial moment, which prompted the interest in Pt(II) and other metal complexes as potential anticancer agents. This chapter highlights the state of the art on metal complexes in cancer therapy, highlighting their uptake mechanisms, biological targets, toxicity, and drug resistance. Finally, based on the importance of selective target of cancer cells, drug delivery systems will also be discussed

    Rhodium catalyzed hydroformylation of kaurane derivatives: A route to new diterpenes with potential bioactivity

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    Kaurenic and grandiflorenic acids are naturally occurring diterpenes whose biological activity has been described. Both acids contain an exocyclic methylenic double bond that allows further functionalization on their structure. In an attempt to expand the number of derivatives of these two natural products, we have undertaken a study on the hydroformylation of the methyl esters of the two acids and the trimethylsilyl ether of kaurenol. These substrates have been hydroformylated by using unmodified Rh catalysts, as well as Rh/PPh3 and Rh/tris-(o-t-butylphenyl)phosphite catalytic systems at 100 °C and 20 bar of CO/H2 (1:1). For the three substrates, the two Rh catalysts modified with P-donor ligands, produced high conversions and chemo- and regioselectivities in the diastereoisomeric pair of linear aldehydes. In all cases, the stereoselectivity observed is strongly dependent of the system used, being the most diastereoselective the least hindered unmodified Rh/CO catalyst. A correlation between the higher diastereoselectivity and the faster [beta]-elimination of the metal-alkyl intermediate observed in the unmodified system is discussed.http://www.sciencedirect.com/science/article/B6TF5-4RVMXFD-3/1/d27e671ad9e0b7fc325dfd0bdf413c7

    Preclinical Evidence Supporting Early Initiation of Citalopram Treatment in Machado-Joseph Disease

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    Spinocerebellar ataxias are dominantly inherited neurodegenerative disorders with no disease-modifying treatment. We previously identified the selective serotonin reuptake inhibitor citalopram as a safe and effective drug to be repurposed for Machado-Joseph disease. Pre-symptomatic treatment of transgenic (CMVMJD135) mice strikingly ameliorated mutant ataxin-3 (ATXN3) pathogenesis. Here, we asked whether citalopram treatment initiated at a post-symptomatic age would still show efficacy. We used a cohort of CMVMJD135 mice that shows increased phenotypic severity and faster disease progression (CMVMJD135hi) compared to the mice used in the first trial. Groups of hemizygous CMVMJD135hi mice were orally treated with citalopram. Behavior, protein analysis, and pathology assessment were performed blindly to treatment. Our results show that even when initiated after symptom onset, treatment of CMVMJD135hi mice with citalopram ameliorated motor coordination and balance, attenuating disease progression, albeit to a lesser extent than that seen with pre-symptomatic treatment initiation. There was no impact on ATXN3 aggregation, which contrasts with the robust reduction in ATXN3-positive inclusions observed in CMVMJD135 mice, when treated pre-symptomatically. Post-symptomatic treatment of CMVMJD135hi mice revealed, however, a limited neuroprotective effect by showing a tendency to repair cerebellar calbindin staining, and to increase the number of motor neurons and of NeuN-positive cells in certain brain regions. While supporting that early initiation of treatment with citalopram leads to a marked increase in efficacy, these results strengthen our previous observation that modulation of serotonergic signaling by citalopram is a promising therapeutic approach for Machado-Joseph disease even after symptom onset.European Regional Development Funds (FEDER), through the Competitiveness Factors Operational Programme (COMPETE), and by National funds, through the Foundation for Science and Technology (FCT), under the scope of the project POCI-01-0145-FEDER-007038. This article has been developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the FEDER. This work was also supported by FCT and COMPETE through the projects [PTDC/SAU-GMG/112617/2009] (to PM) and [EXPL/BIM-MEC/0239/2012] (to AT-C), by FCT through the project [POCI-01-0145-FEDER-016818 (PTDC/NEU-NMC/3648/2014)] (to PM), by National Ataxia foundation (to PM and to AT-C), and by Ataxia UK (to PM). SE, SD-S, SO, and AT-C were supported by the FCT individual fellowships, SFRH/BD/78554/2011, SFRH/BD/78388/2011, PD/BD/127818/2016, and SFRH/BPD/102317/2014, respectively. FCT fellowships are co-financed by POPH, QREN, Governo da República Portuguesa, and EU/FSEinfo:eu-repo/semantics/publishedVersio

    Chronic treatment with 17-DMAG improves balance and coordination in a new mouse model of Machado-Joseph disease

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    Machado-Joseph disease (MJD) or spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disease currently with no treatment. We describe a novel mouse model of MJD which expresses mutant human ataxin-3 at near endogenous levels and manifests MJD-like motor symptoms that appear gradually and progress over time. CMVMJD135 mice show ataxin-3 intranuclear inclusions in the CNS and neurodegenerative changes in key disease regions, such as the pontine and dentate nuclei. Hsp90 inhibition has shown promising outcomes in some neurodegenerative diseases, but nothing is known about its effects in MJD. Chronic treatment of CMVMJD mice with Hsp90 inhibitor 17-DMAG resulted in a delay in the progression of their motor coordination deficits and, at 22 and 24 weeks of age, was able to rescue the uncoordination phenotype to wild-type levels; in parallel, a reduction in neuropathology was observed in treated animals. We observed limited induction of heat-shock proteins with treatment, but found evidence that 17-DMAG may be acting through autophagy, as LC3-II (both at mRNA and protein levels) and beclin-1 were induced in the brain of treated animals. This resulted in decreased levels of the mutant ataxin-3 and reduced intranuclear aggregation of this protein. Our data validate this novel mouse model as a relevant tool for the study of MJD pathogenesis and for pre-clinical studies, and show that Hsp90 inhibition is a promising therapeutic strategy for MJD.We would like to thank to Dr. Henry Paulson for providing the anti-ataxin-3 serum, Dr. Monica Sousa for the pCMV vector and to Eng. Lucilia Goreti Pinto, Lu s Martins, Miguel Carneiro and Celina Barros for technical assistance. This work was supported by Fundacao para a Ciencia e Tecnologia through the projects FEDER/FCT, POCI/SAU-MMO/60412/2004 and PTDC/SAU-GMG/64076/2006. This work was supported by Fundacao para a Ciencia e Tecnologia through fellowships SFRH/BPD/91562/2012 to A.S-F., SFRH/BD/78388/2011 to S. D-S., SFRH/BD/51059/2010 to A.N-C., and SFRH/BPD/79469/2011 to A.T-C.

    N-Domain Isoform of Angiotensin I Converting Enzyme as a Marker of Hypertension: Populational Study

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    The aim of this paper was to investigate the presence of the urinary 90 kDa N-domain ACE in a cohort of the population from Vitoria, Brazil, to verify its association with essential hypertension since this isoform could be a possible genetic marker of hypertension. Anthropometric, clinical, and laboratory parameters of the individuals were evaluated (n=1150) and the blood pressure (BP) was measured. The study population was divided according to ACE isoforms in urine as follows: ACE 65/90/190, presence of three ACE isoforms (n=795), ACE 90+ (65/90) (n=186), and ACE 90− (65/190) (n=169) based on the presence (+) or absence (−) of the 90 kDa ACE isoform. The anthropometric parameters, lipid profile, serum levels of uric acid, glucose, and the systolic and diastolic BP were significantly greater in the ACE 90+ compared with the ACE 90− and ACE 65/90/190 individuals. We found that 98% of individuals from the ACE 90+ group and 38% from the ACE 65/90/190 group had hypertension, compared to only 1% hypertensive individuals in the ACE 90− group. There is a high presence of the 90 kDa N-domain ACE isoform (85%) in the studied population. The percentile of normotensive subjects with three isoforms was 62%. Our findings could contribute to the development of new efficient strategy to prevent and treat hypertension to avoid the development of cardiovascular disease

    Lithium chloride therapy fails to improve motor function in a transgenic mouse model of Machado-Joseph disease

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    The accumulation of misfolded proteins in neurons, leading to the formation of cytoplasmic and nuclear aggregates, is a common theme in age-related neurodegenerative diseases, possibly due to disturbances of the proteostasis and insufficient activity of cellular protein clearance pathways. Lithium is a well-known autophagy inducer that exerts neuroprotective effects in different conditions and has been proposed as a promising therapeutic agent for several neurodegenerative diseases. We tested the efficacy of chronic lithium 10.4 mg/kg) treatment in a transgenic mouse model of Machado-Joseph disease, an inherited neurodegenerative disease, caused by an expansion of a polyglutamine tract within the protein ataxin-3. A battery of behavioral tests was used to assess disease progression. In spite of activating autophagy, as suggested by the increased levels of Beclin-1, Atg7, and LC3II, and a reduction in the p62 protein levels, lithium administration showed no overall beneficial effects in this model concerning motor performance, showing a positive impact only in the reduction of tremors at 24 weeks of age. Our results do not support lithiumchronic treatment as a promising strategy for the treatment of Machado-Joseph disease (MJD).FCT -Fundação para a Ciência e a Tecnologia(SFRH/BD/51059/2010

    Tauroursodeoxycholic Acid Improves Motor Symptoms in a Mouse Model of Parkinson's Disease

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    Parkinson's disease (PD) is characterized by severe motor symptoms, and currently there is no treatment that retards disease progression or reverses damage prior to the time of clinical diagnosis. Tauroursodeoxycholic acid (TUDCA) is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD; however, its effect in PD motor symptoms has never been addressed. In the present work, an extensive behavior analysis was performed to better characterize the MPTP model of PD and to evaluate the effects of TUDCA in the prevention/improvement of mice phenotype. MPTP induced significant alterations in general motor performance paradigms, including increased latency in the motor swimming, adhesive removal and pole tests, as well as altered gait, foot dragging, and tremors. TUDCA administration, either before or after MPTP, significantly reduced the swimming latency, improved gait quality, and decreased foot dragging. Importantly, TUDCA was also effective in the prevention of typical parkinsonian symptoms such as spontaneous activity, ability to initiate movement and tremors. Accordingly, TUDCA prevented MPTP-induced decrease of dopaminergic fibers and ATP levels, mitochondrial dysfunction and neuroinflammation. Overall, MPTP-injected mice presented motor symptoms that are aggravated throughout time, resembling human parkinsonism, whereas PD motor symptoms were absent or mild in TUDCA-treated animals, and no aggravation was observed in any parameter. The thorough demonstration of improvement of PD symptoms together with the demonstration of the pathways triggered by TUDCA supports a subsequent clinical trial in humans and future validation of the application of this bile acid in PD.National funds, through the Foundation for Science and Technology (Portugal) (FCT), under the scope of the projects PTDC/NEU-NMC/0248/2012, UID/DTP/04138/2013 and POCI-01-0145-FEDER-007038, and post-doctoral grants SFRH/BPD72891/2010 (to A.I.R.), SFRH/BPD/95855/2013 (to M.J.N.), SFRH/BPD/98023/2013 (to A.N.C.), SFRH/BPD/91562/2012 (to A.S.F.) and UMINHO/BI/248/2016 (to S.D.S.). This work has also been developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Program (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER), and by FEDER funds, through the Competitiveness Factors Operational Program (COMPETE)info:eu-repo/semantics/publishedVersio

    Building a Portuguese Coalition for Biodiversity Genomics

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    The diverse physiography of the Portuguese land and marine territory, spanning from continental Europe to the Atlantic archipelagos, has made it an important repository of biodiversity throughout the Pleistocene glacial cycles, leading to a remarkable diversity of species and ecosystems. This rich biodiversity is under threat from anthropogenic drivers, such as climate change, invasive species, land use changes, overexploitation or pathogen (re)emergence. The inventory, characterization and study of biodiversity at inter- and intra-specific levels using genomics is crucial to promote its preservation and recovery by informing biodiversity conservation policies, management measures and research. The participation of researchers from Portuguese institutions in the European Reference Genome Atlas (ERGA) initiative, and its pilot effort to generate reference genomes for European biodiversity, has reinforced the establishment of Biogenome Portugal. This nascent institutional network will connect the national community of researchers in genomics. Here, we describe the Portuguese contribution to ERGA’s pilot effort, which will generate high-quality reference genomes of six species from Portugal that are endemic, iconic and/or endangered, and include plants, insects and vertebrates (fish, birds and mammals) from mainland Portugal or the Azores islands. In addition, we outline the objectives of Biogenome Portugal, which aims to (i) promote scientific collaboration, (ii) contribute to advanced training, (iii) stimulate the participation of institutions and researchers based in Portugal in international biodiversity genomics initiatives, and (iv) contribute to the transfer of knowledge to stakeholders and engaging the public to preserve biodiversity. This initiative will strengthen biodiversity genomics research in Portugal and fuel the genomic inventory of Portuguese eukaryotic species. Such efforts will be critical to the conservation of the country’s rich biodiversity and will contribute to ERGA’s goal of generating reference genomes for European species.info:eu-repo/semantics/publishedVersio

    Seeds of Amazonian Fabaceae as a source of new lectins

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    Seeds from fifty native Amazonian Fabaceae species (representing subfamilies Caesalpinioideae, Mimosoideae and Faboideae) were screened for the presence of new lectins. Their crude protein extracts were assayed for hemagglutinating activity (HA). The protein fractions of Anadenanthera peregrina, Dimorphandra caudata, Ormosia lignivalvis and Swartzia laevicarpa exhibited HA, and this activity was inhibited by galactose or lactose but not by glucose or mannose. The crude extract of S. laevicarpa exhibited HA activity only after ion exchange chromatography, and its lectin was further purified by affinity chromatography on immobilized lactose. Despite the large number of lectins that have been reported in leguminous plants, this is the first description of lectins in the genera Anadenanthera, Dimorphandra and Ormosia. The study of lectins from these genera and from Swartzia will contribute to the understanding of the evolutionary relationships of legume lectins in terms of their protein processing properties and structures
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