RESUMO
The differentiation of T cells from lymphoid progenitors in the thymus follows sequential developmental stages that constantly require interaction with thymic epithelial cells. Several distinct aspects of early T cell development depend on the activation of Notch receptors on thymocytes, while the selection of thymocytes at later stages are believed to be Notch independent. Using reverse genetic approaches and whole-thymus live imaging in an in vivo teleost model, the medaka, we report that Notch1 signals is required for proliferation and specification of developing T cells as well as involved in their selection in the thymus. We reveal that Notch1 controls the migratory behavior of thymocytes through controlling the chemokine receptor Ccr9b and thereby influence the T cell receptor (TCR) activation. Hence, we propose that, in lower vertebrates, the function of Notch signaling extends to all stages of T cell development, except when thymocytes undergo TCRß rearrangement.
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Movimento Celular , Proteínas de Peixes/imunologia , Oryzias , Receptor Notch1/deficiência , Transdução de Sinais , Linfócitos T/imunologia , Timo/imunologia , Animais , Movimento Celular/genética , Movimento Celular/imunologia , Proteínas de Peixes/deficiência , Oryzias/genética , Oryzias/imunologia , Receptor Notch1/imunologia , Transdução de Sinais/genética , Transdução de Sinais/imunologiaRESUMO
BACKGROUND: Artemisinin-based combination therapy (ACT) has been the recommended first-line treatment for uncomplicated malaria in Mozambique since 2006, with artemether-lumefantrine (AL) and amodiaquine-artesunate (AS-AQ) as the first choice. To assess efficacy of currently used ACT, an in vivo therapeutic efficacy study was conducted. METHODS: The study was conducted in four sentinel sites: Montepuez, Moatize, Mopeia and Massinga. Patients between 6 and 59 months old with uncomplicated Plasmodium falciparum malaria (2000-200,000 parasites/µl) were enrolled between February and September of 2018, assigned to either an AL or AS-AQ treatment arm, and monitored for 28 days. A Bayesian algorithm was applied to differentiate recrudescence from new infection using genotyping data of seven neutral microsatellites. Uncorrected and PCR-corrected efficacy results at day 28 were calculated. RESULTS: Totals of 368 and 273 patients were enrolled in the AL and AS-AQ arms, respectively. Of these, 9.5% (35/368) and 5.1% (14/273) were lost to follow-up in the AL and AS-AQ arms, respectively. There were 48 and 3 recurrent malaria infections (late clinical and late parasitological failures) in the AL and AS-AQ arms, respectively. The day 28 uncorrected efficacy was 85.6% (95% confidence interval (CI) 81.3-89.2%) for AL and 98.8% (95% CI 96.7-99.8%) for AS-AQ, whereas day 28 PCR-corrected efficacy was 97.9% (95% CI 95.6-99.2%) for AL and 99.6% (95% CI 97.9-100%) for AS-AQ. Molecular testing confirmed that 87.4% (42/48) and 33.3% (1/3) of participants with a recurrent malaria infection in the AL and AS-AQ arms were new infections; an expected finding in a high malaria transmission area. Adverse events were documented in less than 2% of participants for both drugs. CONCLUSION: Both AL and AS-AQ have therapeutic efficacies well above the 90% WHO recommended threshold and remain well-tolerated in Mozambique. Routine monitoring of therapeutic efficacy should continue to ensure the treatments remain efficacious. Trial registration Clinicaltrials.gov: NCT04370977.
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Amodiaquina/uso terapêutico , Antimaláricos/uso terapêutico , Combinação Arteméter e Lumefantrina/uso terapêutico , Artemisininas/uso terapêutico , Malária Falciparum/tratamento farmacológico , Amodiaquina/normas , Antimaláricos/normas , Combinação Arteméter e Lumefantrina/normas , Artemisininas/normas , Pré-Escolar , Combinação de Medicamentos , Humanos , Lactente , Moçambique , Parasitemia/tratamento farmacológico , Segurança , Resultado do TratamentoRESUMO
BACKGROUND: Due to the threat of emerging anti-malarial resistance, the World Health Organization recommends incorporating surveillance for molecular markers of anti-malarial resistance into routine therapeutic efficacy studies (TESs). In 2018, a TES of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) was conducted in Mozambique, and the prevalence of polymorphisms in the pfk13, pfcrt, and pfmdr1 genes associated with drug resistance was investigated. METHODS: Children aged 6-59 months were enrolled in four study sites. Blood was collected and dried on filter paper from participants who developed fever within 28 days of initial malaria treatment. All samples were first screened for Plasmodium falciparum using a multiplex real-time PCR assay, and polymorphisms in the pfk13, pfcrt, and pfmdr1 genes were investigated by Sanger sequencing. RESULTS: No pfk13 mutations, associated with artemisinin partial resistance, were observed. The only pfcrt haplotype observed was the wild type CVMNK (codons 72-76), associated with chloroquine sensitivity. Polymorphisms in pfmdr1 were only observed at codon 184, with the mutant 184F in 43/109 (39.4%) of the samples, wild type Y184 in 42/109 (38.5%), and mixed 184F/Y in 24/109 (22.0%). All samples possessed N86 and D1246 at these two codons. CONCLUSION: In 2018, no markers of artemisinin resistance were documented. Molecular surveillance should continue to monitor the prevalence of these markers to inform decisions on malaria treatment in Mozambique.
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Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Resistência a Medicamentos/genética , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Polimorfismo Genético/genética , Antimaláricos/farmacologia , Artemisininas/farmacologia , Pré-Escolar , Quimioterapia Combinada , Feminino , Marcadores Genéticos , Humanos , Lactente , Masculino , Moçambique , Plasmodium falciparum/isolamento & purificaçãoRESUMO
INTRODUCTION: Treatment of infections that require high-level isolation can cause anxiety and fear among health care workers. Adequate and complete multi-professional simulation-based training could reduce those feelings and improve patient care. OBJECTIVE: The purpose of this study was to assess the impact of multi-professional simulation-based training on the risk perception and preparedness of health care workers (registered nurses, doctors and ancillary staff) who care for patients assessed to be at risk or confirmed to have Ebola, level 3-4 biohazard. METHODS: A prospective before-after study was designed. Health care workers who participated in a multi-professional simulation training course to improve the care of patients potentially infected with Level 3 and 4 biohazards were evaluated about their risk perception. The training was based on clinical scenarios. The evaluation was conducted using questionnaire based on Likert scale. After the training, a satisfaction survey about the most important aspects of the course was also conducted. RESULTS: Fifty-eight health care workers participated in the training course, 22 of whom were registered nurses. Participants presented positive changes after the training, increasing their sense of security, predisposition and confidence (p < 0.000001 for all). CONCLUSION: Multi-professional simulation-based training significantly improves the perception of safety and preparedness of health care workers regarding the care of patients potentially infected with Ebola virus and other Level 3-4 biohazards. RELEVANCE TO CLINICAL PRACTICE: The implementation of educational training strategies - such as simulations - is beneficial in improving the capacity of response and coping, as well as in reducing feelings of fear and insecurity.
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Adaptação Psicológica , Atitude do Pessoal de Saúde , Pessoal de Saúde/educação , Pessoal de Saúde/psicologia , Doença pelo Vírus Ebola/enfermagem , Estresse Ocupacional/terapia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de RiscoRESUMO
One of the fundamental steps toward malaria control is the use of antimalarial drugs. The success of antimalarial treatment can be affected by the presence of drug-resistant populations of Plasmodium falciparum. To assess resistance, we used molecular methods to examine 351 P. falciparum isolates collected from 4 sentinel sites in Mozambique for K13, pfmdr1, pfcrt, and pfdhps polymorphisms and for plasmepsin2 (pfpm2) and pfmdr1 copy numbers. We found multiple copies of pfpm2 in 1.1% of isolates. All isolates carried K13 wild-type alleles (3D7-like), except 4 novel polymorphisms (Leu619Leu, Phe656Ile, Val666Val, Gly690Gly). Prevalence of isolates with pfcrt mutant (K76T) allele was low (2.3%). Prevalence of isolates with pfdhps mutant alleles (A437G and K540E) was >80%, indicating persistence of sulfadoxine/pyrimethamine resistance; however, markers of artemisinin were absent, and markers of piperaquine resistance were low. Piperaquine resistance isolates may spread in Mozambique as dihydroartemisinin/piperaquine drug pressure increases.
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Plasmodium falciparum/efeitos dos fármacos , Alelos , Antimaláricos/farmacologia , Variações do Número de Cópias de DNA/genética , Resistência a Medicamentos/genética , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Moçambique , Plasmodium falciparum/genética , Polimorfismo Genético/genéticaRESUMO
BACKGROUND: Mozambique adopted artemisinin-based combination therapy (ACT) for the treatment of uncomplicated Plasmodium falciparum malaria in the year 2006, and since 2009 artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) have been proposed as alternative first-line treatments. A multicentre study was conducted in five sites across the country to assess the in vivo efficacy and tolerability of these two drugs. METHODS: Children aged six to 59 months with uncomplicated malaria were recruited between June 2011 and January 2012 in five sites across Mozambique (Montepuez, Dondo, Tete, Chokwe, and Manhiça), and treated with AL or ASAQ in a non-randomized study. Follow-up was organized following standard WHO recommendations for in vivo studies, and included daily visits during the three-day-long supervised treatment course, followed by weekly visits up to day 28. The study primary outcome was the day 28 PCR-corrected early treatment failure (ETF), late clinical failure (LCF), late parasitological failure (LPF), and adequate clinical and parasitological response (ACPR). PCR was performed centrally for all cases of recurrent parasitaemia from day 7 onwards to distinguish recrudescence from re-infection. RESULTS: Four-hundred and thirty-nine (AL cohort; five sites) and 261 (ASAQ cohort, three sites) children were recruited to the study. Day 28 PCR-corrected efficacy for AL was 96.0% (335/339; 95% CI: 93.4-97.8), while for ASAQ it was 99.6% (232/233; 95% CI: 97.6-99.9). The majority of recurring parasitaemia cases throughout follow-up were shown to be re-infections by PCR. Both drugs were well tolerated, with the most frequent adverse event being vomiting (AL 4.5% [20/439]; ASAQ 9.6% [25/261]) and no significant events deemed related to the study drugs. CONCLUSION: This study confirms that both AL and ASAQ remain highly efficacious and well tolerated for the treatment of uncomplicated malaria in Mozambican children. Studies such as these should be replicated regularly in the selected surveillance sentinel sites to continuously monitor the efficacy of these drugs and to rapidly detect any potential signs of declining efficacy to ACT, the mainstay of malaria treatment.
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Amodiaquina/uso terapêutico , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Etanolaminas/uso terapêutico , Fluorenos/uso terapêutico , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Amodiaquina/efeitos adversos , Antimaláricos/efeitos adversos , Combinação Arteméter e Lumefantrina , Artemisininas/efeitos adversos , Pré-Escolar , Combinação de Medicamentos , Etanolaminas/efeitos adversos , Feminino , Fluorenos/efeitos adversos , Humanos , Lactente , Estimativa de Kaplan-Meier , Masculino , Moçambique/epidemiologia , Resultado do TratamentoRESUMO
Demyelinating disorders, with a particular focus on multiple sclerosis (MS), have a multitude of detrimental cognitive and physical effects on the patients. Current treatment options that involve substances promoting remyelination fail in the clinics due to difficulties in reaching the central nervous system (CNS). Here, the dual encapsulation of retinoic acid (RA) into lipid nanocapsules with a nominal size of 70 nm, and a low PdI of 0.1, coupled with super paramagnetic iron oxide nanoparticles (SPIONs) was accomplished, and joined by an external functionalization process with a transferrin-receptor binding peptide. This nanosystem showed a 3-fold improved internalization by endothelial cells compared to the free drug, ability to interact with oligodendrocyte progenitor cells and microglia, and improvements in the permeability through the blood-brain barrier by 5-fold. The lipid nanocapsules also induced the differentiation of oligodendrocyte progenitor cells into more mature, myelin producing oligodendrocytes, as evaluated by high-throughput image screening, by 3-5-fold. Furthermore, the ability to tame the inflammatory response was verified in lipopolysaccharide-stimulated microglia, suppressing the production of pro-inflammatory cytokines by 50-70%. Overall, the results show that this nanosystem can act in both the inflammatory microenvironment present at the CNS of affected patients, but also stimulate the differentiation of new oligodendrocytes, paving the way for a promising platform in the therapy of MS.
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Doenças Desmielinizantes , Esclerose Múltipla , Nanocápsulas , Doenças Neurodegenerativas , Animais , Camundongos , Doenças Desmielinizantes/induzido quimicamente , Doenças Desmielinizantes/tratamento farmacológico , Doenças Desmielinizantes/metabolismo , Nanocápsulas/uso terapêutico , Tretinoína/farmacologia , Células Endoteliais/metabolismo , Esclerose Múltipla/tratamento farmacológico , Bainha de Mielina , Inflamação/tratamento farmacológico , Oligodendroglia , Diferenciação Celular , Doenças Neurodegenerativas/tratamento farmacológico , Lipídeos/farmacologia , Camundongos Endogâmicos C57BLRESUMO
Spinal cord injury (SCI) is characterized by neuroinflammatory processes that are marked by an uncontrolled activation of microglia, which directly damages neurons. Natural and synthetic melanins represent an effective tool to treat neuroinflammation because they possess immunomodulatory properties. Here, the main objective was to evaluate the effect of eumelanin-coated poly(lactic acid) (EU@PLA) aligned microfibers on in vitro model of neuroinflammation related to spinal cord injury in terms of inflammatory mediators' modulation. Aligned fibers were chosen to provide physical cues to guide axonal growth in a specific direction thus restoring the synaptic connection. Eumelanin decorated PLA electrospun substrates were produced combining electrospinning, spin coating and solid-state polymerization processes (oxidative coupling under oxygen atmosphere). Biological response in terms of antioxidant and anti-inflammatory activity was analyzed on an in vitro model of neuroinflammation [microglial cells stimulated with lipopolysaccharide (LPS)]. Cell morphology and EU@PLA mechanism of action, in terms of toll-like receptor-4 (TLR-4) involvement were assessed. The results show that EU@PLA fibers were able to decrease reactive oxygen species, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-кB) expression >50 % compared to PLA + LPS and interleukin 6 (IL-6) secretion about 20 %. Finally, the mechanism of action of EU@PLA in microglia was found to be dependent on the TLR-4 signaling. Protein expression analysis revealed a decreased in TLR-4 production induced by LPS stimulation in presence of EU@PLA. Overall, our results show that EU@PLA represents an innovative and effective strategy for the control of inflammatory response in central nervous system.
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Melaninas , Traumatismos da Medula Espinal , Ratos , Animais , Receptor 4 Toll-Like , Ratos Sprague-Dawley , Doenças Neuroinflamatórias , Lipopolissacarídeos/farmacologia , Traumatismos da Medula Espinal/terapia , Traumatismos da Medula Espinal/metabolismo , PoliésteresRESUMO
The inflammasome is a conserved structure for the intracellular detection of danger or pathogen signals. As a large intracellular multiprotein signaling platform, it activates downstream effectors that initiate a rapid necrotic programmed cell death (PCD) termed pyroptosis and activation and secretion of pro-inflammatory cytokines to warn and activate surrounding cells. However, inflammasome activation is difficult to control experimentally on a single-cell level using canonical triggers. We constructed Opto-ASC, a light-responsive form of the inflammasome adaptor protein ASC (Apoptosis-Associated Speck-Like Protein Containing a CARD) which allows tight control of inflammasome formation in vivo. We introduced a cassette of this construct under the control of a heat shock element into zebrafish in which we can now induce ASC inflammasome (speck) formation in individual cells of the skin. We find that cell death resulting from ASC speck formation is morphologically distinct from apoptosis in periderm cells but not in basal cells. ASC-induced PCD can lead to apical or basal extrusion from the periderm. The apical extrusion in periderm cells depends on Caspb and triggers a strong Ca2+ signaling response in nearby cells.
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Inflamassomos , Peixe-Zebra , Animais , Inflamassomos/metabolismo , Peixe-Zebra/metabolismo , Proteínas Adaptadoras de Sinalização CARD/genética , Proteínas Adaptadoras de Sinalização CARD/metabolismo , Apoptose , Piroptose , Caspase 1/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismoRESUMO
The loss of the myelin sheath insulating axons is the hallmark of demyelinating diseases. These pathologies often lead to irreversible neurological impairment and patient disability. No effective therapies are currently available to promote remyelination. Several elements contribute to the inadequacy of remyelination, thus understanding the intricacies of the cellular and signaling microenvironment of the remyelination niche might help us to devise better strategies to enhance remyelination. Here, using a new in vitro rapid myelinating artificial axon system based on engineered microfibres, we investigated how reactive astrocytes influence oligodendrocyte (OL) differentiation and myelination ability. This artificial axon culture system enables the effective uncoupling of molecular cues from the biophysical properties of the axons, allowing the detailed study of the astrocyte-OL crosstalk. Oligodendrocyte precursor cells (OPCs) were cultured on poly(trimethylene carbonate-co-ε-caprolactone) copolymer electrospun microfibres that served as surrogate axons. This platform was then combined with a previously established tissue engineered glial scar model of astrocytes embedded in 1 % (w/v) alginate matrices, in which astrocyte reactive phenotype was acquired using meningeal fibroblast conditioned medium. OPCs were shown to adhere to uncoated engineered microfibres and differentiate into myelinating OL. Reactive astrocytes were found to significantly impair OL differentiation ability, after six and eight days in a co-culture system. Differentiation impairment was seen to be correlated with astrocytic miRNA release through exosomes. We found significantly reduction on the expression of pro-myelinating miRNAs (miR-219 and miR-338) and an increase in anti-myelinating miRNA (miR-125a-3p) content between reactive and quiescent astrocytes. Additionally, we show that OPC differentiation inhibition could be reverted by rescuing the activated astrocytic phenotype with ibuprofen, a chemical inhibitor of the small rhoGTPase RhoA. Overall, these findings show that modulating astrocytic function might be an interesting therapeutic avenue for demyelinating diseases. The use of these engineered microfibres as an artificial axon culture system will enable the screening for potential therapeutic agents that promote OL differentiation and myelination while providing valuable insight on the myelination/remyelination processes.
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Doenças Desmielinizantes , MicroRNAs , Remielinização , Humanos , Astrócitos/metabolismo , Astrócitos/patologia , Remielinização/fisiologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Doenças Desmielinizantes/metabolismo , Doenças Desmielinizantes/patologiaRESUMO
Mozambique is one of the four African countries which account for over half of all malaria deaths worldwide, yet little is known about the parasite genetic structure in that country. We performed P. falciparum amplicon and whole genome sequencing on 2251 malaria-infected blood samples collected in 2015 and 2018 in seven provinces of Mozambique to genotype antimalarial resistance markers and interrogate parasite population structure using genome-wide microhaplotyes. Here we show that the only resistance-associated markers observed at frequencies above 5% were pfmdr1-184F (59%), pfdhfr-51I/59 R/108 N (99%) and pfdhps-437G/540E (89%). The frequency of pfdhfr/pfdhps quintuple mutants associated with sulfadoxine-pyrimethamine resistance increased from 80% in 2015 to 89% in 2018 (p < 0.001), with a lower expected heterozygosity and higher relatedness of microhaplotypes surrounding pfdhps mutants than wild-type parasites suggestive of recent selection. pfdhfr/pfdhps quintuple mutants also increased from 72% in the north to 95% in the south (2018; p < 0.001). This resistance gradient was accompanied by a concentration of mutations at pfdhps-436 (17%) in the north, a south-to-north increase in the genetic complexity of P. falciparum infections (p = 0.001) and a microhaplotype signature of regional differentiation. The parasite population structure identified here offers insights to guide antimalarial interventions and epidemiological surveys.
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Antimaláricos , Malária Falciparum , Malária , Humanos , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Moçambique , Plasmodium falciparum/genética , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malária/tratamento farmacológico , Resistência a Medicamentos/genética , Sequenciamento Completo do Genoma , Estruturas GenéticasRESUMO
Cells are continuously exposed to physical forces and the central nervous system (CNS) is no exception. Cells dynamically adapt their behavior and remodel the surrounding environment in response to forces. The importance of mechanotransduction in the CNS is illustrated by exploring its role in CNS pathology development and progression. The crosstalk between the biochemical and biophysical components of the extracellular matrix (ECM) are here described, considering the recent explosion of literature demonstrating the powerful influence of biophysical stimuli like density, rigidity and geometry of the ECM on cell behavior. This review aims at integrating mechanical properties into our understanding of the molecular basis of CNS disease. The mechanisms that mediate mechanotransduction events, like integrin, Rho/ROCK and matrix metalloproteinases signaling pathways are revised. Analysis of CNS pathologies in this context has revealed that a wide range of neurological diseases share as hallmarks alterations of the tissue mechanical properties. Therefore, it is our belief that the understanding of CNS mechanotransduction pathways may lead to the development of improved medical devices and diagnostic methods as well as new therapeutic targets and strategies for CNS repair.
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The cytokine interleukin 1 (IL-1) is an evolutionary innovation of vertebrates. Fish and amphibian have one IL1 gene, while mammals have two copies of IL1, IL1A and IL1B, with distinct expression patterns and differences in their proteolytic activation. Our current understanding of the evolutionary history of IL-1 is mainly based on phylogenetic analysis, but this approach provides no information on potentially different functions of IL-1 homologues, and it remains unclear which biological activities identified for IL-1α and IL-1ß in mammals are present in lower vertebrates. Here, we use in vitro and in vivo experimental models to examine the expression patterns and cleavage of IL-1 proteins from various species. We found that IL-1 in the teleost medaka shares the transcriptional patterns of mammalian IL-1α, and its processing also resembles that of mammalian IL-1α, which is sensitive to cysteine protease inhibitors specific for the calpain and cathepsin families. By contrast, IL-1 proteins in reptiles also include biological properties of IL-1ß. Therefore, we propose that the duplication of the ancestral IL1 gene led to the segregation of expression patterns and protein processing that characterizes the two extant forms of IL-1 in mammals.
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Evolução Biológica , Vertebrados , Animais , Calpaína/genética , Mamíferos/genética , Filogenia , Vertebrados/genéticaRESUMO
Targeted and specific induction of cell death in an individual or groups of cells hold the potential for new insights into the response of tissues or organisms to different forms of death. Here, we report the development of optogenetically controlled cell death effectors (optoCDEs), a novel class of optogenetic tools that enables light-mediated induction of three types of programmed cell death (PCD)-apoptosis, pyroptosis, and necroptosis-using Arabidopsis thaliana photosensitive protein Cryptochrome-2. OptoCDEs enable a rapid and highly specific induction of PCD in human, mouse, and zebrafish cells and are suitable for a wide range of applications, such as sub-lethal cell death induction or precise elimination of single cells or cell populations in vitro and in vivo. As the proof-of-concept, we utilize optoCDEs to assess the differences in neighboring cell responses to apoptotic or necrotic PCD, revealing a new role for shingosine-1-phosphate signaling in regulating the efferocytosis of the apoptotic cell by epithelia.
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Apoptose , Necroptose , Optogenética , Piroptose , Animais , Apoptose/genética , Arabidopsis/genética , Criptocromos/genética , Humanos , Lisofosfolipídeos/metabolismo , Camundongos , Necroptose/genética , Piroptose/genética , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Peixe-Zebra/genéticaRESUMO
Therapeutic strategies aimed at overcoming the loss of myelin sheath in central nervous system demyelinating diseases are often unsuccessful due to nescience underlying the mechanisms of remyelination failure. The environment surrounding a demyelination lesion is seen as a hostile terrain, characterized by factors that can inhibit myelin production by oligodendrocytes (OLs). The formation of a glial scar containing reactive astrocytes producing high amounts of altered matrix proteins can compromise OL remyelination. Allied to glial scar, mechanical properties of the tissue are altered. The paradigms in the remyelination failure are changing. We point mechanobiology as a missing key towards unravelling the nature of (de)myelination. Mechanical cues as stiffness, axonal tension or physical constraints are emerging as dictators of tissue homeostasis and pathology. Here we delve into an in-depth characterization of the preeminent models to study mechanobiology events of (de)myelination and remyelination. Alternatives to in vivo systems are provided, either through the exploration of simpler animal models, creation of in vitro models using tissue engineered approaches or through in silico tools. We discuss how bioengineering is being explored to generate relevant models to dissect new mechanobiology mechanisms and identify novel therapeutic targets, being expected to profoundly impact the treatment of demyelinating diseases.
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Doenças Desmielinizantes , Remielinização , Animais , Bioengenharia , Biofísica , Doenças Desmielinizantes/metabolismo , Doenças Desmielinizantes/patologia , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Remielinização/fisiologiaRESUMO
BACKGROUND: Seasonal malaria chemoprevention (SMC) is a highly effective community-based intervention to prevent malaria infections in areas where the malaria burden is high and transmission occurs mainly during the rainy season. In Africa, so far, SMC has been implemented in the Sahel region. Mozambique contributes 4% of the global malaria cases, and malaria is responsible for one-quarter of all deaths in the country. Based on recommendations in the Malaria Strategic Plan, the Malaria Consortium, in partnership with the National Malaria Control Programme in Mozambique, initiated a phased SMC implementation study in the northern province of Nampula. The first phase of this 2-year implementation study was conducted in 2020-2021 and focused on the feasibility and acceptability of SMC. The second phase will focus on demonstrating impact. This paper describes phase 2 of the implementation study. OBJECTIVE: Specific objectives include the following: (1) to determine the effectiveness of SMC in terms of its reduction in incidence of malaria infection among children aged 3 to 59 months; (2) to determine the chemoprevention efficacy of sulfadoxine-pyrimethamine plus amodiaquine (SP+AQ) when used for SMC in Nampula Province, Mozambique, and the extent to which efficacy is impacted by drug resistance and drug concentrations; (3) to investigate the presence and change in SP+AQ- and piperaquine-resistance markers over time as a result of SMC implementation; and (4) to understand the impact of the SMC implementation model, determining the process and acceptability outcomes for the intervention. METHODS: This type 2, hybrid, effectiveness-implementation study uses a convergent mixed methods approach. SMC will be implemented in four monthly cycles between December 2021 and March 2022 in four districts of Nampula Province. Phase 2 will include four components: (1) a cluster randomized controlled trial to establish confirmed malaria cases, (2) a prospective cohort to determine the chemoprevention efficacy of the antimalarials used for SMC and whether drug concentrations or resistance influence the duration of protection, (3) a resistance marker study in children aged 3 to 59 months to describe changes in resistance marker prevalence over time, and (4) a process evaluation to determine feasibility and acceptability of SMC. RESULTS: Data collection began in mid-January 2022, and data analysis is expected to be completed by October 2022. CONCLUSIONS: This is the first effectiveness trial of SMC implemented in Mozambique. The findings from this trial will be crucial to policy change and program expansion to other suitable geographies outside of the Sahel. The chemoprevention efficacy cohort study is a unique opportunity to better understand SMC drug efficacy in this new SMC environment. TRIAL REGISTRATION: ClinicalTrials.gov NCT05186363; https://clinicaltrials.gov/ct2/show/NCT05186363. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/36403.
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Parkinson's disease's etiology is unknown, although evidence suggests the involvement of oxidative modifications of intracellular components in disease pathobiology. Despite the known involvement of the extracellular matrix in physiology and disease, the influence of oxidative stress on the matrix has been neglected. The chemical modifications that might accumulate in matrix components due to their long half-live and the low amount of extracellular antioxidants could also contribute to the disease and explain ineffective cellular therapies. The enriched striatal extracellular matrix from a mouse model of Parkinson's disease was characterized by Raman spectroscopy. We found a matrix fingerprint of increased oxalate content and oxidative modifications. To uncover the effects of these changes on brain cells, we morphologically characterized the primary microglia used to repopulate this matrix and further quantified the effects on cellular mechanical stress by an intracellular fluorescence resonance energy transfer (FRET)-mechanosensor using the U-2 OS cell line. Our data suggest changes in microglia survival and morphology, and a decrease in cytoskeletal tension in response to the modified matrix from both hemispheres of 6-hydroxydopamine (6-OHDA)-lesioned animals. Collectively, these data suggest that the extracellular matrix is modified, and underscore the need for its thorough investigation, which may reveal new ways to improve therapies or may even reveal new therapies.
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Retinitis Pigmentosa (RP) is an inherited disorder of retinal degeneration with progressive loss of rod and cone photoreceptors. RPE65 is a gene encoding the trans-cis isomerase which is essential for the classical visual cycle. While most RPE65 mutations associated with RP have been reported as autosome, an Irish c.1430A > G (p.D477G) mutation is the first case reported to cause dominantly inherited RP. In this study, we used the non-integrational Sendai virus to generate induced pluripotent stem cell (iPSC) lines carrying the c.1430A > G (p.D477G) mutation from three familial RP patients.
Assuntos
Células-Tronco Pluripotentes Induzidas/metabolismo , Retinose Pigmentar/genética , cis-trans-Isomerases/genética , Animais , Feminino , Humanos , Masculino , MutaçãoRESUMO
BACKGROUND: The World Health Organization (WHO) launched an initiative to plan for the sustainability of integrated community case management (iCCM) programmes supported by the Rapid Access Expansion (RAcE) Programme in five African countries in 2016. WHO contracted experts to facilitate sustainability planning among Ministries of Health, WHO, nongovernmental organisation grantees, and other stakeholders. METHODS: We designed an iterative and unique process for each RAcE project area which involved creating a sustainability framework to guide planning; convening meetings to identify and prioritise elements of the framework; forming technical working groups to build country ownership; and, ultimately, creating roadmaps to guide efforts to fully transfer ownership of the iCCM programmes to host countries. For this analysis, we compared priorities identified in roadmaps across RAcE project sites, examined progress against roadmaps via transition plans, and produced recommendations for short-term actions based on roadmap priorities that were unaddressed or needed further attention. RESULTS: This article describes the sustainability planning process, roadmap priorities, progress against roadmaps, and recommendations made for each project area. We found a few patterns among the prioritised roadmap elements. Overall, every project area identified priorities related to policy and coordination of external stakeholders including funders; supply chain management; service delivery and referral system; and communication and social mobilisation, indicating that these factors have persisted despite iCCM programme maturity, and are also of concern to new programmes. We also found that a facilitated process to identify and document programme priorities in roadmaps, along with deliberately planning for transition from an external implementer to a national system could support the sustainability of iCCM programmes by facilitating teams of stakeholders to accomplish explicit tasks related to transitioning the programme. CONCLUSIONS: Certain common elements are of concern for sustaining iCCM programmes across countries, among them political leadership, supply chain management, data processes, human resources, and community engagement. Adapting and using a sustainability planning approach created an inclusive and comprehensive dialogue about systemic factors that influence the sustainability of iCCM services and facilitated changes to health systems in each country.
Assuntos
Administração de Caso/organização & administração , Serviços de Saúde Comunitária/organização & administração , África , Humanos , Avaliação de Programas e Projetos de Saúde , Organização Mundial da SaúdeRESUMO
After spinal cord injury (SCI), nerve regeneration is severely hampered due to the establishment of a highly inhibitory microenvironment at the injury site, through the contribution of multiple factors. The potential of antisense oligonucleotides (AONs) to modify gene expression at different levels, allowing the regulation of cell survival and cell function, together with the availability of chemically modified nucleic acids with favorable biopharmaceutical properties, make AONs an attractive tool for novel SCI therapy developments. In this work, we explored the potential of locked nucleic acid (LNA)-modified AON gapmers in combination with a fibrin hydrogel bridging material to induce gene silencing in situ at a SCI lesion site. LNA gapmers were effectively developed against two promising gene targets aiming at enhancing axonal regeneration-RhoA and GSK3ß. The fibrin-matrix-assisted AON delivery system mediated potent RNA knockdown in vitro in a dorsal root ganglion explant culture system and in vivo at a SCI lesion site, achieving around 75% downregulation 5 days after hydrogel injection. Our results show that local implantation of a AON-gapmer-loaded hydrogel matrix mediated efficient gene silencing in the lesioned spinal cord and is an innovative platform that can potentially combine gene regulation with regenerative permissive substrates aiming at SCI therapeutics and nerve regeneration.