27,706 research outputs found

    Vascular nitrosative stress in hypertension induced by fetal undernutrition in rats

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    Fetal undernutrition predisposes to hypertension development. Since nitric oxide (NO) is a key factor in blood pressure control, we aimed to investigate the role of NO alterations in hypertension induced by fetal undernutrition in rats. Male and female offspring from dams exposed to undernutrition during the second half of gestation (MUN) were studied at 21 days (normotensive) and 6 months of age (hypertension developed only in males). In aorta, we analyzed total and phosphorylated endothelial NO synthase (eNOS, p-eNOS), 3-nitrotyrosine (3-NT), and Nrf2 (Western blot). In plasma we assessed l-arginine, asymmetric and symmetric dimethylarginine (ADMA, SDMA; LC–MS/MS), nitrates (NOx, Griess reaction), carbonyl groups, and lipid peroxidation (spectrophotometry). In iliac arteries, we studied superoxide anion production (DHE staining, confocal microscopy) and vasodilatation to acetylcholine (isometric tension). Twenty-one-day-old MUN offspring did not show alterations in vascular e-NOS or 3NT expression, plasma l-Arg/ADMA ratio, or NOx. Compared to control group, 6-month-old MUN rats showed increased aortic expression of p-eNOS/eNOS and 3-NT, being Nrf2 expression lower, elevated plasma l-arginine/ADMA, NOx and carbonyl levels, increased iliac artery DHE staining and reduced acetylcholine-mediated relaxations. These alterations in MUN rats were sex-dependent, affecting males. However, females showed some signs of endothelial dysfunction. We conclude that increased NO production in the context of a pro-oxidative environment, leads to vascular nitrosative damage and dysfunction, which can participate in hypertension development in MUN males. Females show a better adaptation, but signs of endothelial dysfunction, which can explain hypertension in ageingOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Natur

    Iodate respiration by Azoarcus sp. DN11 and its potential use for removal of radioiodine from contaminated aquifers

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    Azoarcus sp. DN11 was previously isolated from gasoline-contaminated groundwater as an anaerobic benzene-degrading bacterium. Genome analysis of strain DN11 revealed that it contained a putative idr gene cluster (idrABP1P2), which was recently found to be involved in bacterial iodate (IO3−) respiration. In this study, we determined if strain DN11 performed iodate respiration and assessed its potential use to remove and sequester radioactive iodine (129I) from subsurface contaminated aquifers. Strain DN11 coupled acetate oxidation to iodate reduction and grew anaerobically with iodate as the sole electron acceptor. The respiratory iodate reductase (Idr) activity of strain DN11 was visualized on non-denaturing gel electrophoresis, and liquid chromatography–tandem mass spectrometry analysis of the active band suggested the involvement of IdrA, IdrP1, and IdrP2 in iodate respiration. The transcriptomic analysis also showed that idrA, idrP1, and idrP2 expression was upregulated under iodate-respiring conditions. After the growth of strain DN11 on iodate, silver-impregnated zeolite was added to the spent medium to remove iodide from the aqueous phase. In the presence of 200 μM iodate as the electron acceptor, more than 98% of iodine was successfully removed from the aqueous phase. These results suggest that strain DN11 is potentially helpful for bioaugmentation of 129I-contaminated subsurface aquifers

    The enterovirus genome can be translated in an IRES-independent manner that requires the initiation factors eIF2A/eIF2D

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    RNA recombination in positive-strand RNA viruses is a molecular-genetic process, which permits the greatest evolution of the genome and may be essential to stabilizing the genome from the deleterious consequences of accumulated mutations. Enteroviruses represent a useful system to elucidate the details of this process. On the biochemical level, it is known that RNA recombination is catalyzed by the viral RNA-dependent RNA polymerase using a template-switching mechanism. For this mechanism to function in cells, the recombining genomes must be located in the same subcellular compartment. How a viral genome is trafficked to the site of genome replication and recombination, which is membrane associated and isolated from the cytoplasm, is not known. We hypothesized that genome translation was essential for colocalization of genomes for recombination. We show that complete inactivation of internal ribosome entry site (IRES)-mediated translation of a donor enteroviral genome enhanced recombination instead of impairing it. Recombination did not occur by a nonreplicative mechanism. Rather, sufficient translation of the nonstructural region of the genome occurred to support subsequent steps required for recombination. The noncanonical translation initiation factors, eIF2A and eIF2D, were required for IRES-independent translation. Our results support an eIF2A/eIF2D-dependent mechanism under conditions in which the eIF2-dependent mechanism is inactive. Detection of an IRES-independent mechanism for translation of the enterovirus genome provides an explanation for a variety of debated observations, including nonreplicative recombination and persistence of enteroviral RNA lacking an IRES. The existence of an eIF2A/eIF2D-dependent mechanism in enteroviruses predicts the existence of similar mechanisms in other viruses

    Selenium nanoparticles modulate histone methylation via lysine methyltransferase activity and S-adenosylhomocysteine depletion

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    At physiological levels, the trace element selenium plays a key role in redox reactions through the incorporation of selenocysteine in antioxidant enzymes. Selenium has also been evaluated as a potential anti-cancer agent, where selenium nanoparticles have proven effective, and are well tolerated in vivo at doses that are toxic as soluble Se. The use of such nanoparticles, coated with either serum albumin or the naturally occurring alkaline polysaccharide chitosan, also serves to enhance biocompatibility and bioavailability. Here we demonstrate a novel role for selenium in regulating histone methylation in ovarian cancer cell models treated with inorganic selenium nanoparticles coated with serum albumin or chitosan. As well as inducing thioredoxin reductase expression, ROS activity and cancer cell cytotoxicity, coated nanoparticles caused significant increases in histone methylation. Specifically, selenium nanoparticles triggered an increase in the methylation of histone 3 at lysines K9 and K27, histone marks involved in both the activation and repression of gene expression, thus suggesting a fundamental role for selenium in these epigenetic processes. This direct function was confirmed using chemical inhibitors of the histone lysine methyltransferases EZH2 (H3K27) and G9a/EHMT2 (H3K9), both of which blocked the effect of selenium on histone methylation. This novel role for selenium supports a distinct function in histone methylation that occurs due to a decrease in S-adenosylhomocysteine, an endogenous inhibitor of lysine methyltransferases, the metabolic product of methyl-group transfer from S-adenosylmethionine in the one-carbon metabolism pathway. These observations provide important new insights into the action of selenium nanoparticles. It is now important to consider both the classic antioxidant and novel histone methylation effects of this key redox element in its development in cancer therapy and other applications

    Characterization of Dutch-Cocoa produced using potash extract from cocoa pod husk as an alkalizing bioresource

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    Abstract Alkalizing agents in the processing of Dutch-Cocoa are often imported from developing countries. This occurs amidst humongous quantities of Cocoa Pod Husk (CPH) that are largely rotting away. This study therefore appraises the inherent alkalizing potentials of CPH, including its physicochemical and safety characteristics in the production of Dutch-Cocoa. CPH was calcined, potash extracted, characterized, and applied in formulation (1% to 5% conc.) in Dutch-production of Cocoa. Quality parameters of the resultant product were analyzed following AOAC procedures (p ≤ 0.05). In addition, rats(n=30) were fed it over a 21-day duration while nutritional and safety indicators were monitored. Sensory properties were also evaluated. The results showed some predominant properties of CPH potash extract [Potassium 35.7%, pH 12.3, alkalinity 15.6 g/100 g CO3] and Dutch-cocoa [protein (15.8% to 16.5%), colour (Hunter L,a,b) 36.9, 8.8, 11.7 light - dark red), dispersibility (1.5 to 2.3), wettability (143.7 s), sedimentation (20.7% to 49.3%)] which favourably compared with commercial variants. Apparent digestibility (AD%) was significant (Protein 86%, Fat 88%, Fiber 66% etc) (p ≤ .0.05). Safety indices exhibited no deleterious effect and the product was adjudged acceptable. Dutch-cocoa produced using CPH-derived-potash as an alternate alkalizing bioresource is feasible, while simultaneously providing an environmentally friendly outlet for CP

    In vitro acetylcholinesterase inhibitory activity and chemical composition of the dichloromethane extracts of the leaves and inflorescences of the tumbleweed, Trachyandra laxa (N.E.Br.) Oberm. var. rigida (Suesseng.) Roessl

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    Trachyandra laxa, which belongs to the family Asphodelaceae, is a poisonous geophyte, often consumed by livestock, particularly when pastures are poor. Ingestion of T. laxa by livestock causes paresis and paralysis of the animals. However, the chemical composition of this plant has never been studied before and its toxic components are still unknown. In this study, an acetylcholinesterase (AChE) inhibition assay of different extracts of the parts of Trachyandra laxa (N.E.Br.) Oberm. var. rigida (Suesseng.) Roessl. revealed that the DCM extracts possess the highest AChE inhibitory activity. In addition, using qualitative phytochemical tests, it was determined that all the plant parts contain polyphenols and tannins, while only the leaves contain flavonoids. Saponins were detected in all plant parts, except in the flowers and anthraquinones were detected in all plant parts expect the roots. Using GC MS analysis, 13 volatile constituents were identified in the DCM extracts of the leaves and inflorescences, including a,b-unsaturated lactones, carboxylic acids and esters, a diterpenoid, phytol, and a phytosterol, b-sitosterol. Of particular interest are the a,b-unsaturated lactones, which were identified as dihydroactinidiolide (DHA) and its hydroxylated analogue, hydroxy‑DHA, as well as phytol, a diterpenoid. DHA and phytol have been reported to possess potent AChE inhibition activity. It is therefore plausible that these compounds and potentially also hydroxy‑DHA could contribute to the AChE inhibitory activity of the DCM extracts, and thus the neurotoxicity of T. laxa var. rigida

    Innate immunity and metabolism in the bovine ovarian follicle

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    Postpartum uterine disease in dairy cows is associated with reduced fertility. One of the first and most prevalent bacteria associated with uterine disease is Escherichia coli. The bacterial endotoxin, lipopolysaccharide (LPS), accumulates in the ovarian follicular fluid of animals with uterine disease. The granulosa cells of the ovarian follicle respond to LPS by secreting pro-inflammatory cytokines, such as interleukin (IL)-1a, IL-1b and IL-8, and oocyte health is perturbed. Dairy cows also experience metabolic energy stress in the postpartum period, which is associated with an increased risk of developing uterine disease and ovarian dysfunction. This thesis explored the crosstalk between innate immunity and metabolic energy stress in bovine granulosa cells and cumulus-oocyte complex. Firstly, we found that glycolysis, AMP-activated protein kinase and the mechanistic target of rapamycin, regulate the innate immune responses to LPS in granulosa cells isolated from bovine ovarian follicles. Activation of AMP-activated protein kinase decreased the LPS-induced secretion of IL-1a, IL-1b, and IL8, and was associated with shortened duration of ERK1/2 and JNK phosphorylation. Next, we found that decreasing the availability of cholesterol or inhibiting cholesterol biosynthesis using short-interfering RNA impaired the LPS-induced secretion of IL-1a and IL-1b by granulosa cells. Furthermore, metabolic energy stress or inhibiting cholesterol biosynthesis in the bovine cumulus-oocyte complex modulated the innate immune responses to LPS, and perturbed meiotic progression during in vitro maturation. Finally, we explored an in vivo model of uterine disease in heifers, using RNAseq to investigate alterations to the transcriptome of the reproductive tract. We found that uterine disease altered the transcriptome of the endometrium, oviduct, granulosa cells and oocyte, several months after bacterial infusion; these changes were most evident in the granulosa cells and oocyte of the ovarian follicle. The findings from this thesis imply that there is crosstalk between innate immunity and metabolism in the bovine ovarian follicle

    Characterization And Manipulation Of O-Glcnacylation In Granulosa Cells Of Bovine Ovarian Antral Follicles

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    Glucose is widely recognized as the preferred energy substrate for metabolism by granulosa cells (GCs). Yet in most cells, 2-5% of glucose is shunted through the hexosamine biosynthesis pathway (HBP) for O-linked N-acetylglucosaminylation (O-GlcNAcylation). O-GlcNAcylation is an evolutionarily-conserved, post-translational process that modifies serine and threonine residues on a variety of proteins. O-GlcNAcylation is also considered a nutrient sensor that can regulate cellular processes such as metabolism, signal transduction, and proliferation. In this respect, O-GlcNAcylation may be similar to, and possibly mediate, AMP-activated protein kinase (AMPK) signaling and its nutrient-sensing actions. However, the occurrence of O-GlcNAcylation and its relative importance to GC function has not been determined. Here, we characterized relative O-GlcNAcylation in bovine GCs from small and large antral follicles and determined its effects on GC proliferation. Bovine ovary pairs morphologically staged to the mid-to-late estrous period were used. Granulosa cells and follicular fluid were aspirated from small (3-5mm) and large (\u3e10mm) follicles. Freshly isolated GCs of small follicles exhibited greater immunodetectable expression of O-GlcNAcylation and the O-GlcNAcylation enzyme, O-GlcNAc transferase (OGT) expression than large follicles (P\u3c0.05, n=7 ovary pairs). Less glucose (0.4mM vs 2.2 mM, P\u3c0.05) and more lactate (33.3mM vs 9.6mM, P\u3c0.05) was present in the follicular fluid of small follicles compared to large follicles (P\u3c0.05, n=7). Steroid profiles revealed a progesterone to estradiol ratio \u3e10 in all small follicle pools, indicative of highly atretic follicles. Similarly, 5 of the 7 large follicles pools were highly atretic and 2 were intermediately atretic (\u3e1\u3c10). Culture of GCs in serum free conditions revealed that inhibition of the HBP via the glutamine fructose-6-phosphate aminotransferase (GFAT) inhibitor, DON (50µM), impaired O-GlcNAcylation for both follicle sizes (P\u3c0.05, n=5 independent expts.). The inhibitor DON also prevented GC proliferation regardless of follicle size (P\u3c0.05, n=4). Direct inhibition of O-GlcNAcylation via the OGT inhibitor, OSMI-1 (50µM), prevented proliferation of GCs from small follicles (P\u3c0.05, n=3). Augmentation of O-GlcNAcylation via the O-GlcNAcase (OGA) inhibitor, Thiamet-G (2.5µM), enhanced O-GlcNAcylation in GCs from both follicle sizes (P\u3c0.05, n=3) but had no effect (P\u3e0.05, n=3) on GC proliferation for either follicle size. Lastly, the use of the AMPK activator, Metformin (10mM), revealed that while AMPK activation inhibited GC proliferation from small follicles (P\u3c0.05, n=4) as anticipated, it had no effect on O-GlcNAcylation (P\u3e0.05 n=5). The results indicate that: 1) O-GlcNAcylation occurs in GCs of bovine antral follicles, 2) Relative expression of O-GlcNAcylation is associated with alterations of glucose and lactate within the follicle, 3) Disruption of O-GlcNAcylation impairs GC proliferation, and 4) AMPK activation does not affect O-GlcNAcylation. In conclusion, the HBP and O-GlcNAcylation in GCs constitute an alternative, potential nutrient-sensing pathway to influence GC function and folliculogenesis in the bovine ovary

    Utility of ultra-sensitive qPCR to detect Plasmodium falciparum and Plasmodium vivax infections under different transmission intensities

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    Background: The use of molecular diagnostics has revealed an unexpectedly large number of asymptomatic low-density malaria infections in many malaria endemic areas. This study compared the gains in parasite prevalence obtained by the use of ultra-sensitive (us)-qPCR as compared to standard qPCR in cross-sectional surveys conducted in Thailand, Brazil and Papua New Guinea (PNG). The compared assays differed in the copy number of qPCR targets in the parasite genome. Methods: Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) parasites were quantified by qPCR amplifying the low-copy Pf_ and Pv_18S rRNA genes or the multi-copy targets Pf_varATS and Pv_mtCOX1. Cross-sectional surveys at the three study sites included 2252 participants of all ages and represented different transmission intensities. Results: In the two low-transmission areas, P. falciparum positivity was 1.3% (10/773) (Thailand) and 0.8% (5/651) (Bra- zil) using standard Pf_18S rRNA qPCR. In these two countries, P. falciparum positivity by Pf_varATS us-qPCR increased to 1.9% (15/773) and 1.7% (11/651). In PNG, an area with moderate transmission intensity, P. falciparum positivity significantly increased from 8.6% (71/828) by standard qPCR to 12.2% (101/828) by us-qPCR. The proportions of P. falciparum infections not detected by standard qPCR were 33%, 55% and 30% in Thailand, Brazil and PNG. Plasmodium vivax was the predominating species in Thailand and Brazil, with 3.9% (30/773) and 4.9% (32/651) positivity by Pv_18S rRNA qPCR. In PNG, P. vivax positivity was similar to P. falciparum, at 8.0% (66/828). Use of Pv_mtCOX1 us-qPCR led to a significant increase in positivity to 5.1% (39/773), 6.4% (42/651) and 11.5% (95/828) in Thailand, Brazil, and PNG. The proportions of P. vivax infections missed by standard qPCR were similar at all three sites, with 23%, 24% and 31% in Thailand, Brazil and PNG. Conclusion: The proportional gains in the detection of P. falciparum and P. vivax infections by ultra-sensitive diag- nostic assays were substantial at all three study sites. Thus, us-qPCR yields more precise prevalence estimates for both P. falciparum and P. vivax at all studied levels of endemicity and represents a significant diagnostic improvement

    Desenvolvimento de testes genéticos por PCR em tempo-real para diagnóstico rápido de LHON e surdez

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    Mitochondrial cytopathies are a set of diseases caused by a disturbance in the cell energy production. Mitochondrial dysfunction impairs efficiency of the mitochondrial respiratory chain (MRC) and ATP production, affecting the organism’s energetic equilibrium. Pathogenic sequence variants in mitochondrial DNA (mtDNA) that lead to these pathologies are more frequent in tissues that need higher energy levels to function. The presented work looks into two such diseases: Leber’s Hereditary Optic Neuropathy and mitochondrial non-syndromic Hearing Loss (MNSHL). LHON is characterized by presence of genetic alterations in mtDNA, with three main primary pathogenic sequence variants existing, which represent 90-95% of LHON cases with an identified genetic cause: m.3460G>A, in ND1 subunit gene; m.11778G>A, in ND4 subunit gene; and m.14484T>C, in ND6 subunit gene. All of these are subunits of the MRC’s complex I. These mtDNA variations lead to mitochondrial dysfunction in complex I, creating ATP depletion, reactive oxygen species (ROS) increase and oxidative stress. LHON is commonly characterized by a sequential vision loss and, within 1 year of symptoms starting, 97% of patients with vision loss in one eye develop loss in the second. Therapy administration yields good outcomes, if done in a short-time span after first vision loss. It is essential to quickly and reliably scan for pathogenic sequence variants, in order to act timely and rescue function. Mitochondrial non-syndromic hearing loss and deafness (MNSHL) is characterized by sensorineural hearing loss (SNHL). This type of hearing loss, particularly when induced by aminoglycosides, has also three primary pathogenic sequence variants associated with ototoxicity: m.1494C>T and m.1555A>G, both in the MTRNR1 gene, and m.7445A>G, in the MTCO1 and MTTS1 genes. These are responsible for ATP depletion, an increase of ROS and oxidative stress, due to alterations in the mitochondrial ribosome or tRNA. In MNSHL, the cochlea is the affected tissue. With this disorder the principal modifier factor is the administration of aminoglycosides, a type of antibiotics, which trigger a cascade, that leads the individual permanently deaf. The best course of action is prevention, and to ensure clinical action is not dramatically slowed down, results that show whether administration is safe or not need to be quick. The aim of this work, for both diseases, is the development of a screening method characterized by fast and reliable approach for genetic assessment, to be used for clinical guidance, particularly in therapeutics. For LHON, the screening method is based on real-time PCR with High-Resolution Melting (HRM) analysis, for detection of the TOP-3 pathogenic sequence variants, by assessing the amplicon’s Tm. In this case, 94 samples were analyzed, including LHON suspected patients, relatives, other mitochondrial disease patients and healthy controls. All samples were previously classified by another method, having then been blinded before the performance of this work. For analysis, Real-Time PCR was run in triplicates, to allow for a more robust HRM analysis. The software had the ability to classify samples as different variants, wild-type or mutant; information which was then crossed with the previous classification of the sample to assess the success of the software classification. Samples were correctly assigned. This approach provides results in a quick fashion that guides clinical action in a timely fashion. The presence of other polymorphisms in the amplicons might be a hindrance to the robustness of the results provided by this technique and their effect on variant classification needs to be considered. For this, a predictive in-silico analysis was performed, regarding all described variants’ presence in the sequences in analysis. Accordingly, an additional complementary method may be necessary for assurance of result’s specificity. For MNSHL, the screening method was also real-time PCR based, but this one was performed with Amplification-Refractory Mutation System (ARMS) primers, designed for the pathogenic sequence variants previously associated in literature for the MNSHL. Discrimination of results was done based on amplification in positive cases and lack of it in negative cases. This approach analyzed 32 samples, including MNSHL suspected patients, their relatives, other mitochondrial disease patients and healthy controls, but only results concerning the m.1555A>G were obtained timely. All samples were previously classified by another method, having then been blinded before performance of this work. For optimization, Real-Time PCR was run in duplicates, to increase robustness of analysis. The Real-Time software showed if samples amplified as wild-type or mutant, with classification following. This data was crossed with previous known classification of the samples to assess the success of the approach. All analyzed samples were correctly identified with this approach. However, two of the three pathogenic sequence variants did not achieve implementation within the timeframe necessary for their inclusion, namely m.1494C>T and m.7445A>G. The optimization of their screening was not possible and further work is necessary to optimize and implement the approach concerning the analysis for these variants. In conclusion, it was possible to implement an analysis method for LHON’s TOP-3 pathogenic sequence variants within 24h, which represents a big step in precision medicine for diagnosis of this disease. On the other hand, although the implementation was not concluded, a similar approach was started for MNSHL – that, when concluded, will have an enormous impact in preventing aminoglycoside induced HL. This work represents a high impact scientific contribution in reverse translational research.As citopatias mitocondriais são um conjunto de doenças causadas por um distúrbio na produção de energia celular. A disfunção mitocondrial prejudica a eficiência da cadeia respiratória mitocondrial (CRM) e a produção de ATP, afetando o equilíbrio energético do organismo. As variações de sequência patogénicas no DNA mitocondrial (mtDNA) que levam a estas patologias são mais frequentes em tecidos que necessitam de maiores níveis de energia para funcionar. O presente trabalho explora duas dessas doenças: Neuropatia ótica hereditária de Leber (LHON) e Surdez mitocondrial induzida por aminoglicosídeos. A LHON é caracterizada pela presença de alterações genéticas do mtDNA, existindo três variações de sequência patogénicas primárias principais, que representam 90-95% de casos de LHON com identificação da causa genética: m.3460G>A, no gene que codifica a subunidade ND1; m.11778G>A, no gene que codifica a subunidade ND4; e m.14484T>C, no gene que codifica a subunidade ND6. Todas estas subunidades pertencem ao complexo I da CRM. Estas alterações no mtDNA levam a disfunção mitocondrial no complexo I, criando depleção de ATP, aumento de espécies reativas de oxigénio (ROS) e stresse oxidativo. A LHON é comummente caracterizada pela perda sequencial de visão e, 1 ano após o início dos sintomas, 97% dos casos com perda de visão num olho desenvolvem perda de visão no segundo. A administração de terapia produz bons resultados, quando realizada num curto período de tempo após a primeira perda de visão. Assim, é essencial pesquisar variações de sequência patogénicas genéticas de forma rápida e fiável, para atuar rapidamente e recuperar a função visual. A Surdez mitocondrial não-sindrómica (MNSHL), em particular a induzida por aminoglicosídeos, tem também três mutações principais associadas à perda de audição: m.1494C>T e m.1555A>G, ambas no gene MTRNR1, e m.7445A>G, nos genes MTCO1 e MTTS1. Estas são responsáveis pela depleção de ATP, aumento de ROS e stresse oxidativo, devido a alterações no ribossoma ou no tRNA mitocondrial. Aqui, o tecido afetado é a cóclea. Nesta doença, o fator modificador em destaque é a administração de antibióticos de tipo aminoglicosídeos, que despoletam uma cascata de acontecimentos, levando à surdez permanente. A melhor estratégia passa pela prevenção, enquanto ao mesmo tempo se garante que a ação clínica não sofre atrasos. Desta forma, são necessários resultados rápidos, que demonstrem se a administração será segura ou não. O objetivo deste trabalho, para ambas as doenças, é o desenvolvimento de um método de screening, caracterizado por uma abordagem rápida e fiável, usado para guiar a decisão clínica, particularmente na terapêutica. Para a LHON, o método de screening é baseado em PCR em tempo-real com análise de High-Resolution Melting (HRM), para deteção das variantes patogénicas TOP-3, avaliando as Tm dos amplicons. Neste caso, foram analisadas 94 amostras, incluindo doentes com suspeita de LHON, familiares, outros doentes com suspeita de outra doença mitocondrial e controlos saudáveis. Todas as amostras foram previamente classificadas por outro método, tendo sido sujeitas a anonimização antes da realização do trabalho. Para a análise, a PCR em tempo-real foi realizada em triplicados, para permitir uma análise de HRM mais robusta. O software teve a capacidade de classificar amostras como diferentes variantes, ou seja, normal ou mutante. Esta informação foi cruzada com as classificações previamente existentes para avaliar o sucesso da classificação pelo software. As amostras foram corretamente classificadas. Esta abordagem fornece resultados de forma rápida, podendo guiar a ação clínica em tempo útil. A presença de outros polimorfismos nos amplicons poderão obstruir a robustez dos resultados fornecidos por esta técnica e o seu efeito na classificação de variantes precisa de ser considerado. Por esta razão, foi realizada uma análise de previsão in-silico, considerando a presença de todas as variantes descritas. Nesse sentido, pode ser necessário um método complementar de análise para assegurar a especificidade dos resultados. Para a Surdez mitocondrial não-sindrómica, o método de screening baseou-se também na PCR em tempo-real, mas foi realizada com primers de Amplification-Refractory mutation system (ARMS), desenhados para as variantes de sequência patogénicas associadas à MNSHL induzida por aminoglicosídeos, previamente descritas na literatura para esta doença. A discriminação de resultados foi feita com base na presença/ausência de amplificação para cada variante. Foram analisadas 32 amostras com esta abordagem, incluindo doentes com suspeita de MNSHL, seus familiares, doentes com suspeita de outra doença mitocondrial e controlos saudáveis, mas apenas foram obtidos resultados em tempo útil para a m.1555A>G. Todas as amostras tinham sido previamente classificadas por outro método, tendo sido anonimizadas antes da realização do trabalho. Para a otimização, a PCR em tempo-real foi realizada em duplicados, aumentando a robustez da análise. O software de tempo-real mostrou quais as amostras que amplificaram como normais ou mutantes, permitindo a classificação das mesmas. Os dados foram comparados com as classificações previamente conhecidas, para avaliar o sucesso da abordagem em estudo. Todas as amostras em análise foram corretamente identificadas. No entanto, duas das três variantes patogénicas não foram implementadas em tempo útil para inclusão neste trabalho. Para a m.1494C>T e a m.7445A>G, a otimização não foi possível, e será necessário trabalho adicional no futuro, para a implementação da análise destas variantes. Em conclusão, foi possível implementar um método da análise das variantes genéticas TOP-3 da LHON em 24h, o que representa um grande passo na medicina de precisão para diagnóstico desta doença. Por outro lado, apesar de não ter sido concluída a implementação, iniciou-se uma abordagem semelhante para a MNSHL – que, quando for concluída, terá um enorme impacto para evitar a perda auditiva por exposição a aminoglicosídeos. Este trabalho representa uma contribuição científica de alto impacto na investigação translacional reversa.O Laboratório de Biomedicina Mitocondrial e Teranóstica recebeu apoio financeiro da Santhera Pharmaceuticals que permitiu implementação do projeto nacional “Investigação Translacional Epidemiológica, Bigenómica e Funcional nas Atrofias Ópticas” (IP Professora Doutora Manuela Grazina). Apoio financeiro do CNC.IBILI no âmbito do Plano Estratégico UID/NEU/04539/2019.Mestrado em Biologia Aplicad
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