RESUMO
Fragile-X Syndrome (FXS) is the leading monogenetic cause of intellectual disability among children but remains without a cure. Using the Fmr1 KO mouse model of FXS, much work has been done to understand FXS hippocampus dysfunction. Purinergic signaling, where ATP and its metabolites are used as signaling molecules, participates in hippocampus development, but it is unknown if purinergic signaling is affected in the developing Fmr1 KO hippocampus. In our study, we characterized the purinergic receptor P2X7. We first found that P2X7 was reduced in Fmr1 KO whole hippocampus tissue at P14 and P21, corresponding to the periods of neurite outgrowth and synaptic refinement in the hippocampus. We then evaluated the cell-specific expression of P2X7 with immunofluorescence and found differences between WT and Fmr1 KO mice in P2X7 colocalization with hippocampal microglia and neurons. P2X7 colocalized more with microglia at P14 and P21, but there was a sex-specific reduction in P2X7 colocalization with neurons. In contrast, male mice at P14 and P21 showed reduced neuronal P2X7 colocalization compared to females, but only females showed reduced absolute neuronal P2X7 expression across the dorsal hippocampal formation. Together, our results suggest that P2X7 expression is altered during Fmr1-KO hippocampal development, potentially influencing several developmental processes in the Fmr1-KO hippocampus formation.
Assuntos
Proteína do X Frágil da Deficiência Intelectual , Hipocampo , Neurônios , Receptores Purinérgicos P2X7 , Animais , Feminino , Masculino , Camundongos , Proteína do X Frágil da Deficiência Intelectual/genética , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Síndrome do Cromossomo X Frágil/genética , Hipocampo/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/metabolismo , Neurônios/metabolismo , Receptores Purinérgicos P2X7/metabolismo , Receptores Purinérgicos P2X7/genéticaRESUMO
The Communities Organizing to Promote Equity (COPE) Project was implemented in 20 counties across Kansas to build capacity to address health equity by forming local health equity action teams (LHEATS), hiring and training community health workers, facilitating state-wide learning collaboratives, and tailoring communication strategies. We conducted interviews and focus groups with project stakeholders who identified pragmatic recommendations related to LHEAT formation and leadership, establishing trust, nurturing autonomy, and optimizing impact. Insights can improve future community-based health equity efforts. (Am J Public Health. 2024;114(S7):S570-S574. https://doi.org/10.2105/AJPH.2024.307802).
Assuntos
Grupos Focais , Equidade em Saúde , Kansas , Humanos , Equidade em Saúde/organização & administração , Agentes Comunitários de Saúde/organização & administração , Promoção da Saúde/organização & administração , Fortalecimento Institucional/organização & administração , Liderança , Entrevistas como AssuntoRESUMO
BACKGROUND: The Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) is a prospective, longitudinal study of a representative cohort of older adults living in Northern Ireland, United Kingdom. Its aim is to explore the social, behavioural, economic and biological factors of ageing and how these factors change as people age. The study has been designed to maximize comparability with other international studies of ageing thereby facilitating cross-country comparisons. This paper provides an overview of the design and methodology of the health assessment which was carried out as part of Wave 1. METHODS: Three thousand, six hundred and fifty five community dwelling adults, aged 50 years and over participated in the health assessment as part of Wave 1 of NICOLA. The health assessment included a battery of measurements across various domains that addressed key indicators of ageing namely: physical function, vision and hearing, cognitive function, and cardiovascular health. This manuscript describes the scientific rationale for the choice of assessments, provides an overview of the core objective measures carried out in the health assessment and describes the differences in characteristics of participants who took part in the health assessment compared to those who did not take part. RESULTS: The manuscript highlights the importance of incorporating objective measures of health in population based studies as a means of complementing subjective measures and as a way to advance our understanding of the ageing process. The findings contextualize NICOLA as a data resource within Dementias Platform UK (DPUK), the Gateway to Global Ageing (G2G) and other existing networks of population based longitudinal studies of ageing. CONCLUSION: This manuscript can help inform design considerations for other population based studies of ageing and facilitate cross-country comparative analysis of key life-course factors affecting healthy ageing such as educational attainment, diet, the accumulation of chronic conditions (including Alzheimer's disease, dementia and cardiovascular disease) as well as welfare and retirement policies.
Assuntos
Envelhecimento , Humanos , Pessoa de Meia-Idade , Idoso , Estudos Longitudinais , Estudos Prospectivos , Irlanda do Norte , Envelhecimento/psicologia , Estudos de CoortesRESUMO
Fragile X syndrome (FXS) is a genetic disorder that is characterized by a range of cognitive and behavioral deficits, including mild-moderate intellectual disability. The disease is characterized by an X-linked mutation of the Fmr1 gene, which causes silencing of the gene coding for fragile X mental retardation protein (FMRP), a translational regulator integral for neurodevelopment. Mitochondrial dysfunction has been recently associated with FXS, with reports of increases in oxidative stress markers, reactive oxygen species, and lipid peroxidation being present in the brain tissue. Astrocytes, a prominent glial cell within the central nervous system (CNS), play a large role in regulating oxidative homeostasis within the developing brain and dysregulation of astrocyte redox balance in FXS, which may contribute to oxidative stress. Astrocyte function and mitochondrial bioenergetics are significantly influenced by oxygen availability and circulating sex hormones; yet, these parameters are rarely considered during in vitro experimentation. Given that the brain normally develops in a range of hypoxic conditions and FXS is a sex-linked genetic disorder, we investigated how different oxygen levels (normoxic vs. hypoxic) and biological sex affected mitochondrial bioenergetics of astrocytes in FXS. Our results demonstrate that both mitochondrial respiration capacity and reactive oxygen species emission are altered with Fmr1 deletion in astrocytes and these changes were dependent upon both sexual dimorphism and oxygen availability.
Assuntos
Astrócitos/metabolismo , Metabolismo Energético/fisiologia , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Mitocôndrias/metabolismo , Caracteres Sexuais , Animais , Hipóxia Celular/fisiologia , Células Cultivadas , Córtex Cerebral/metabolismo , Feminino , Proteína do X Frágil da Deficiência Intelectual/antagonistas & inibidores , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/genética , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Knockout , Mitocôndrias/genética , Espécies Reativas de Oxigênio/metabolismoRESUMO
Fragile X syndrome (FXS) is the leading monogenic cause of intellectual disability and autism spectrum disorders. With increasing investigation into the molecular mechanisms underlying FXS, there is growing evidence that perturbations in glial signaling are widely associated with neurological pathology. Purinergic signaling, which utilizes nucleoside triphosphates as signaling molecules, provides one of the most ubiquitous signaling systems for glial-neuronal and glial-glial crosstalk. Here, we sought to identify whether purinergic signaling is dysregulated within the FXS mouse cortex, and whether this dysregulation contributes to aberrant intercellular communication. In primary astrocyte cultures derived from the Fmr1 knockout (KO) mouse model of FXS, we found that application of exogenous ATP and UTP evoked elevated intracellular calcium responses compared to wildtype levels. Accordingly, purinergic P2Y2 and P2Y6 receptor expression was increased in Fmr1 KO astrocytes both in vitro and in acutely dissociated tissue, while P2Y antagonism via suramin prevented intracellular calcium elevations, suggesting a role for these receptors in aberrant FXS astrocyte activation. To investigate the impact of elevated purinergic signaling on astrocyte-mediated synaptogenesis, we quantified synaptogenic protein TSP-1, known to be regulated by P2Y activation. TSP-1 secretion and expression were both heightened in Fmr1 KO vs wildtype astrocytes following UTP application, while naïve TSP-1 cortical expression was also transiently elevated in vivo, indicating increased potential for excitatory TSP-1-mediated synaptogenesis in the FXS cortex. Together, our results demonstrate novel and significant purinergic signaling elevations in Fmr1 KO astrocytes, which may serve as a potential therapeutic target to mitigate the signaling aberrations observed in FXS.
Assuntos
Síndrome do Cromossomo X Frágil , Animais , Astrócitos/metabolismo , Modelos Animais de Doenças , Proteína do X Frágil da Deficiência Intelectual/genética , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Camundongos , Camundongos KnockoutRESUMO
In teleost fish, specialized oxygen (O2) chemoreceptors, called neuroepithelial cells (NECs), are found in the gill epithelium in adults. During development, NECs are present in the skin before the formation of functional gills. NECs are known for retaining the monoamine neurotransmitter, serotonin (5-HT) and are conventionally identified through immunoreactivity with antibodies against 5-HT or synaptic vesicle protein (SV2). However, identification of NECs in live tissue and isolated cell preparations has been challenging due to the lack of a specific marker. The present study explored the use of the transgenic zebrafish, ETvmat2:GFP, which expresses green fluorescent protein (GFP) under the control of the vesicular monoamine transporter 2 (vmat2) regulatory element, to identify NECs. Using immunohistochemistry and confocal microscopy, we confirmed that the endogenous GFP in ETvmat2:GFP labelled serotonergic NECs in the skin of larvae and in the gills of adults. NECs of the gill filaments expressed a higher level of endogenous GFP compared with other cells. The endogenous GFP also labelled intrabranchial neurons of the gill filaments. Flow cytometric analysis demonstrated that filamental NECs could be distinguished from other dissociated gill cells based on high GFP expression alone. Acclimation to 2 weeks of severe hypoxia (PO2 = 35 mmHg) induced an increase in filamental NEC frequency, size and GFP gene expression. Here we present for the first time a transgenic tool that labels O2 chemoreceptors in an aquatic vertebrate and its use in high-throughput experimentation.
Assuntos
Genes Reporter/genética , Células Neuroepiteliais/metabolismo , Animais , Animais Geneticamente Modificados , Imuno-Histoquímica , Peixe-ZebraRESUMO
The COVID-19 pandemic has had a major impact on clinical practice. Safe standards of practice are essential to protect health care workers while still allowing them to provide good care. The Canadian Society of Clinical Neurophysiologists, the Canadian Association of Electroneurophysiology Technologists, the Association of Electromyography Technologists of Canada, the Board of Registration of Electromyography Technologists of Canada, and the Canadian Board of Registration of Electroencephalograph Technologists have combined to review current published literature about safe practices for neurophysiology laboratories. Herein, we present the results of our review and provide our expert opinion regarding the safe practice of neurophysiology during the COVID-19 pandemic in Canada.
Assuntos
COVID-19/prevenção & controle , Eletroencefalografia/métodos , Eletromiografia/métodos , Condução Nervosa , Canadá , Estimulação Encefálica Profunda , Técnicas de Diagnóstico Neurológico , Eletrodiagnóstico/métodos , Humanos , Controle de Infecções/métodos , Isoladores de Pacientes , Equipamento de Proteção Individual , Distanciamento Físico , SARS-CoV-2 , Triagem/métodos , Estimulação do Nervo VagoRESUMO
High-altitude natives have evolved to overcome environmental hypoxia and provide a compelling system to understand physiological function during reductions in oxygen availability. The sympathoadrenal system plays a key role in responses to acute hypoxia, but prolonged activation of this system in chronic hypoxia may be maladaptive. Here, we examined how chronic hypoxia exposure alters adrenal catecholamine secretion and how adrenal function is altered further in high-altitude natives. Populations of deer mice (Peromyscus maniculatus) native to low and high altitudes were each born and raised in captivity at sea level, and adults from each population were exposed to normoxia or hypobaric hypoxia for 5 mo. Using carbon fiber amperometry on adrenal slices, catecholamine secretion evoked by low doses of nicotine (10 µM) or acute hypoxia (Po2 â¼15-20 mmHg) was reduced in lowlanders exposed to hypobaric hypoxia, which was attributable mainly to a decrease in quantal charge rather than event frequency. However, secretion evoked by high doses of nicotine (50 µM) was unaffected. Hypobaric hypoxia also reduced plasma epinephrine and protein expression of 3,4-dihydroxyphenylalanine (DOPA) decarboxylase in the adrenal medulla of lowlanders. In contrast, highlanders were unresponsive to hypobaric hypoxia, exhibiting typically low adrenal catecholamine secretion, plasma epinephrine, and DOPA decarboxylase. Highlanders also had consistently lower catecholamine secretion evoked by high nicotine, smaller adrenal medullae with fewer chromaffin cells, and a larger adrenal cortex compared with lowlanders across both acclimation environments. Our results suggest that plastic responses to chronic hypoxia along with evolved changes in adrenal function attenuate catecholamine release in deer mice at high altitude.
Assuntos
Medula Suprarrenal/metabolismo , Altitude , Catecolaminas/metabolismo , Regulação da Expressão Gênica/fisiologia , Peromyscus/metabolismo , Distribuição Animal , Animais , Catecolaminas/genética , Hipóxia , Nicotina/farmacologia , Oxigênio , Consumo de Oxigênio/fisiologiaRESUMO
Highly pathogenic avian influenza (HPAI) outbreaks are devastating to poultry industries and pose a risk to human health. There is concern that demand for free-range poultry products could increase the number of HPAI outbreaks by increasing the potential for low pathogenic avian influenza (LPAI) introduction to commercial flocks. We formulate stochastic mathematical models to understand how poultry-housing (barn, free-range and caged) within the meat and layer sectors interacts with a continuous low-level risk of introduction from wild birds, heterogeneity in virus transmission rates and virus mutation probabilities, to affect the risk of HPAI emergence - at both the shed and industry scales. For H5 and H7 viruses, restricted mixing in caged systems, free-range outdoor access and, particularly, production cycle length significantly influence HPAI risk between sectors of the chicken production industry. Results demonstrate how delay between virus mutation and detection, ensuing from the short production cycle, large shed sizes and industry reporting requirements, could mean that HPAI emerges in meat-production sheds but is undetected with few birds affected. We also find that the Australian HPAI outbreak history appears to be better explained by low LPAI introduction rates and low mutation probabilities, rather than extremely rare introduction and relatively high mutation probabilities.
Assuntos
Criação de Animais Domésticos/métodos , Vírus da Influenza A/patogenicidade , Influenza Aviária/epidemiologia , Animais , Austrália/epidemiologia , Simulação por Computador , Surtos de Doenças , Abrigo para Animais , Vírus da Influenza A/genética , Influenza Aviária/prevenção & controle , Modelos Biológicos , Mutação , Aves Domésticas , Fatores de Risco , Processos EstocásticosRESUMO
Adrenal catecholamine (CAT) secretion is a general physiological response of animals to environmental stressors such as hypoxia. This represents an important adaptive mechanism to maintain homeostasis and protect vital organs such as the brain. In adult mammals, CAT secretory responses are triggered by activation of the sympathetic nervous system that supplies cholinergic innervation of adrenomedullary chromaffin cells (AMC) via the splanchnic nerve. In the neonate, the splanchnic innervation of AMC is immature or absent, yet hypoxia stimulates a non-neurogenic CAT secretion that is critical for adaptation to extra-uterine life. This non-neurogenic, hypoxia-sensing mechanism in AMC is gradually lost or suppressed postnatally along a time course that parallels the development of splanchnic innervation. Moreover, denervation of adult AMC results in a gradual return of the direct hypoxia-sensing mechanism. The signaling pathways by which neonatal AMC sense acute hypoxia leading to non-neurogenic CAT secretion and the mechanisms that underlie the re-acquisition of hypoxia-sensing properties by denervated adult AMC, are beginning to be understood. This review will focus on current views concerning the mechanisms responsible for direct acute hypoxia sensing and CAT secretion in perinatal AMC and how they are regulated by innervation during postnatal development. It will also briefly discuss plasticity mechanisms likely to contribute to CAT secretion during exposures to chronic and intermittent hypoxia.
Assuntos
Catecolaminas/metabolismo , Células Cromafins/metabolismo , Hipóxia/metabolismo , Animais , Plasticidade Celular , Humanos , Canais Iônicos/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
BACKGROUND: Smoking is the most important individual risk factor for many cancer sites but its association with breast and prostate cancer is not entirely clear. Rate advancement periods (RAPs) may enhance communication of smoking related risk to the general population. Thus, we estimated RAPs for the association of smoking exposure (smoking status, time since smoking cessation, smoking intensity, and duration) with total and site-specific (lung, breast, colorectal, prostate, gastric, head and neck, and pancreatic) cancer incidence and mortality. METHODS: This is a meta-analysis of 19 population-based prospective cohort studies with individual participant data for 897,021 European and American adults. For each cohort we calculated hazard ratios (HRs) for the association of smoking exposure with cancer outcomes using Cox regression adjusted for a common set of the most important potential confounding variables. RAPs (in years) were calculated as the ratio of the logarithms of the HRs for a given smoking exposure variable and age. Meta-analyses were employed to summarize cohort-specific HRs and RAPs. RESULTS: Overall, 140,205 subjects had a first incident cancer, and 53,164 died from cancer, during an average follow-up of 12 years. Current smoking advanced the overall risk of developing and dying from cancer by eight and ten years, respectively, compared with never smokers. The greatest advancements in cancer risk and mortality were seen for lung cancer and the least for breast cancer. Smoking cessation was statistically significantly associated with delays in the risk of cancer development and mortality compared with continued smoking. CONCLUSIONS: This investigation shows that smoking, even among older adults, considerably advances, and cessation delays, the risk of developing and dying from cancer. These findings may be helpful in more effectively communicating the harmful effects of smoking and the beneficial effect of smoking cessation.
Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias Pulmonares/epidemiologia , Neoplasias da Próstata/epidemiologia , Abandono do Hábito de Fumar/estatística & dados numéricos , Fumar , Neoplasias da Mama/prevenção & controle , Estudos de Coortes , Feminino , Humanos , Incidência , Neoplasias Pulmonares/prevenção & controle , Masculino , Modelos de Riscos Proporcionais , Estudos Prospectivos , Neoplasias da Próstata/prevenção & controle , Fatores de Risco , Fumar/epidemiologia , Fumar/terapiaAssuntos
Aranha Marrom Reclusa , Edema da Córnea/diagnóstico , Endotélio Corneano/imunologia , Sistema Imunitário/patologia , Picada de Aranha/diagnóstico , Transtornos da Visão/diagnóstico , Animais , Antibacterianos/uso terapêutico , Edema da Córnea/tratamento farmacológico , Dexametasona/uso terapêutico , Combinação de Medicamentos , Endotélio Corneano/efeitos dos fármacos , Glucocorticoides/uso terapêutico , Humanos , Sistema Imunitário/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Picada de Aranha/tratamento farmacológico , Tobramicina/uso terapêutico , Transtornos da Visão/tratamento farmacológicoRESUMO
The clinical and histopathological distinctions between inherited versus acquired bone marrow failure and myelodysplastic syndromes are challenging. The identification of inherited bone marrow failure/myelodysplastic syndromes is critical to inform appropriate clinical management. To investigate whether a subset of pediatric and young adults undergoing transplant for aplastic anemia or myelodysplastic syndrome have germline mutations in bone marrow failure/myelodysplastic syndrome genes, we performed a targeted genetic screen of samples obtained between 1990-2012 from children and young adults with aplastic anemia or myelodysplastic syndrome transplanted at the Fred Hutchinson Cancer Research Center. Mutations in inherited bone marrow failure/myelodysplastic syndrome genes were found in 5.1% (5/98) of aplastic anemia patients and 13.6% (15/110) of myelodysplastic syndrome patients. While the majority of mutations were constitutional, a RUNX1 mutation present in the peripheral blood at a 51% variant allele fraction was confirmed to be somatically acquired in one myelodysplastic syndrome patient. This highlights the importance of distinguishing germline versus somatic mutations by sequencing DNA from a second tissue or from parents. Pathological mutations were present in DKC1, MPL, and TP53 among the aplastic anemia cohort, and in FANCA, GATA2, MPL, RTEL1, RUNX1, SBDS, TERT, TINF2, and TP53 among the myelodysplastic syndrome cohort. Family history or physical examination failed to reliably predict the presence of germline mutations. This study shows that while any single specific bone marrow failure/myelodysplastic syndrome genetic disorder is rare, screening for these disorders in aggregate identifies a significant subset of patients with inherited bone marrow failure/myelodysplastic syndrome.
Assuntos
Anemia Aplástica/genética , Mutação em Linhagem Germinativa , Síndromes Mielodisplásicas/genética , Adolescente , Adulto , Criança , Pré-Escolar , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Família , Feminino , Testes Genéticos , Humanos , Lactente , Masculino , Mutação , Análise de Sequência de DNA , Adulto JovemRESUMO
KEY POINTS: We investigated the role of the neurotrophin BDNF signalling via the TrkB receptor in rat adrenomedullary chromaffin cells (AMCs) exposed to normoxia (Nox; 21% O2) and chronic hypoxia (CHox; 2% O2) in vitro for â¼ 48 h. TrkB receptor expression was upregulated in primary AMCs and in immortalized chromaffin (MAH) cells exposed to CHox; this effect was absent in MAH cells deficient in the transcription factor, hypoxia inducible factor (HIF)-2α. Relative to normoxic controls, activation of the TrkB receptor in chronically hypoxic AMCs led to a marked increase in membrane excitability, intracellular [Ca(2+)], and catecholamine secretion. The BDNF-induced rise of intracellular [Ca(2+)] in CHox cells was sensitive to the selective T-type Ca(2+) channel blocker TTA-P2 and tetrodotoxin (TTX), suggesting key roles of low threshold T-type Ca(2+) and voltage-gated Na(+) channels in the signalling pathway. Environmental stressors, including chronic hypoxia, enhance the ability of adrenomedullary chromaffin cells (AMCs) to secrete catecholamines; however, the underlying molecular mechanisms remain unclear. Here, we investigated the role of brain-derived neurotrophic factor (BDNF) signalling in rat AMCs exposed to chronic hypoxia. In rat adrenal glands, BDNF and its tropomyosin-related kinase B (TrkB) receptor are highly expressed in the cortex and medulla, respectively. Exposure of AMCs to chronic hypoxia (2% O2; 48 h) in vitro caused a significant increase to TrkB mRNA expression. A similar increase was observed in an immortalized chromaffin cell line (MAH cells); however, it was absent in MAH cells deficient in the transcription factor HIF-2α. A specific TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF), stimulated quantal catecholamine secretion from chronically hypoxic (CHox; 2% O2) AMCs to a greater extent than normoxic (Nox; 21% O2) controls. Activation of TrkB by BDNF or 7,8-DHF increased intracellular Ca(2+) ([Ca(2+)]i), an effect that was significantly larger in CHox cells. The 7,8-DHF-induced [Ca(2+)]i rise was sensitive to the tyrosine kinase inhibitor K252a and nickel (2 mm), but not the Ca(2+) store-depleting agent cyclopiazonic acid. Blockade of T-type calcium channels with TTA-P2 (1 µm) or voltage-gated Na(+) channels with TTX inhibited BDNF-induced [Ca(2+)]i increases. BDNF also induced a dose-dependent enhancement of action potential firing in CHox cells. These data demonstrate that during chronic hypoxia, enhancement of BDNF-TrkB signalling increases voltage-dependent Ca(2+) influx and catecholamine secretion in chromaffin cells, and that T-type Ca(2+) channels play a key role in the signalling pathway.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Catecolaminas/metabolismo , Células Cromafins/metabolismo , Oxigênio/metabolismo , Transdução de Sinais , Animais , Canais de Cálcio Tipo T/metabolismo , Hipóxia Celular , Células Cultivadas , Exocitose , Ratos , Ratos Wistar , Receptor trkB/genética , Receptor trkB/metabolismoRESUMO
Aplastic anemia in the neonate is rare. We report a case of severe combined immunodeficiency (SCID) presenting with neonatal aplastic anemia. This report highlights the importance of considering SCID early in the evaluation of neonatal aplastic anemia prior to the development of infectious complications.
Assuntos
Anemia Aplástica , Imunodeficiência Combinada Severa , Anemia Aplástica/complicações , Anemia Aplástica/patologia , Anemia Aplástica/terapia , Humanos , Recém-Nascido , Masculino , Imunodeficiência Combinada Severa/complicações , Imunodeficiência Combinada Severa/patologia , Imunodeficiência Combinada Severa/terapiaRESUMO
The cellular activation of conventional protein kinase C (PKC) isozymes is initiated by the binding of their C2 domains to membranes in response to elevations in intracellular Ca(2+). Following this C2 domain-mediated membrane recruitment, the C1 domain binds its membrane-embedded ligand diacylglycerol, resulting in activation of PKC. Here we explore the molecular mechanisms by which the C2 domain controls the initial step in the activation of PKC. Using stopped-flow fluorescence spectroscopy to measure association and dissociation rate constants, we show that hydrophobic interactions are the major driving force in the binding of the C2 domain to anionic membranes, whereas electrostatic interactions dominate in membrane retention. Specifically, mutation of select hydrophobic or select basic residues in the Ca(2+)-binding loops reduces membrane affinity by distinct mechanisms; mutation of hydrophobic residues primarily alters association rate constants, whereas mutation of charged residues affects dissociation rate constants. Live cell imaging reveals that introduction of these mutations into full-length PKCα not only reduces the Ca(2+)-dependent translocation to plasma membrane but, by impairing the plasma membrane-sensing role of the C2 domain, causes phorbol ester-triggered redistribution of PKCα to other membranes, such as the Golgi. These data underscore the key role of the C2 domain in driving conventional PKC isozymes to the plasma membrane and reveal that not only the amplitude but also the subcellular location of conventional PKC signaling can be tuned by altering the affinity of this module for membranes.
Assuntos
Cálcio/metabolismo , Membrana Celular/enzimologia , Proteína Quinase C-alfa/metabolismo , Animais , Células COS , Membrana Celular/genética , Chlorocebus aethiops , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/fisiologia , Interações Hidrofóbicas e Hidrofílicas , Isoenzimas/genética , Isoenzimas/metabolismo , Cinética , Mutação , Proteína Quinase C-alfa/genética , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Ratos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Eletricidade EstáticaRESUMO
Although mentoring is an important aspect of implementing evidence-based practice (EBP), few models exist for EBP education. The EBP Academy is an innovative, 6-month educational program designed to develop clinical staff as EBP nurse mentors. Sessions provide protected time for participants to work on their EBP projects with assigned mentors who have EBP expertise and similar clinical or research interests. Participants develop EBP projects focused on improving care in their clinical areas. Evaluation of the EBP Academy is based on a four-level model, including participant feedback about the program, perception of meeting program objectives, ability to apply knowledge to practice through EBP projects, and outcome data measured as a result of implementing the EBP changes. By developing EBP mentors, capacity to move nursing practice to a stronger evidence-based foundation can be enhanced. Positive, professional nursing and patient outcomes have been demonstrated when structured EBP education is provided.
Assuntos
Educação Continuada em Enfermagem/métodos , Prática Clínica Baseada em Evidências/educação , Mentores/educação , Recursos Humanos de Enfermagem Hospitalar/educação , Terapia Respiratória/educação , Humanos , Modelos Educacionais , Pesquisa em Avaliação de Enfermagem , Desenvolvimento de ProgramasRESUMO
The symptoms of fragile X syndrome (FXS), caused by a single gene mutation to Fmr1, have been increasingly linked to disordered astrocyte signalling within the cerebral cortex. We have recently demonstrated that the purinergic signalling pathway, which utilizes nucleoside triphosphates and their metabolites to facilitate bidirectional glial and glial-neuronal interactions, is upregulated in cortical astrocytes derived from the Fmr1 knockout (KO) mouse model of FXS. Heightened Fmr1 KO P2Y purinergic receptor levels were correlated with prolonged intracellular calcium release, elevated synaptogenic protein secretion, and hyperactivity of developing circuits. However, due to the relative lack of sensitive and reproducible quantification methods available for measuring purines and pyrimidines, determining the abundance of these factors in Fmr1 KO astrocytes was limited. We therefore developed a hydrophilic interaction liquid chromatography protocol coupled with mass spectrometry to compare the abundance of intracellular and extracellular purinergic molecules between wildtype and Fmr1 KO mouse astrocytes. Significant differences in the concentrations of UDP, ATP, AMP, and adenosine intracellular stores were found within Fmr1 KO astrocytes relative to WT. The extracellular level of adenosine was also significantly elevated in Fmr1 KO astrocyte-conditioned media in comparison to media collected from WT astrocytes. Glycosylation of the astrocyte membrane-bound CD39 ectonucleotidase, which facilitates ligand breakdown following synaptic release, was also elevated in Fmr1 KO astrocyte cultures. Together, these differences demonstrated further dysregulation of the purinergic signalling system within Fmr1 KO cortical astrocytes, potentially leading to significant alterations in FXS purinergic receptor activation and cellular pathology.
Assuntos
Astrócitos , Córtex Cerebral , Proteína do X Frágil da Deficiência Intelectual , Síndrome do Cromossomo X Frágil , Camundongos Knockout , Transdução de Sinais , Animais , Astrócitos/metabolismo , Camundongos , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/metabolismo , Proteína do X Frágil da Deficiência Intelectual/genética , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Córtex Cerebral/metabolismo , Córtex Cerebral/citologia , Apirase/genética , Apirase/metabolismo , Células Cultivadas , Trifosfato de Adenosina/metabolismo , Meios de Cultivo Condicionados , Adenosina/metabolismo , Adenosina/análogos & derivados , Receptores Purinérgicos P2Y/metabolismo , Receptores Purinérgicos P2Y/genética , Camundongos Endogâmicos C57BL , Antígenos CDRESUMO
PURPOSE: Epigenetic modifications including DNA methylation (DNAm) are proposed mechanisms by which social or environmental exposures may influence health and behaviours as we age. The Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) DNAm cohort, established in 2013, is one of several worldwide, nationally representative prospective studies of ageing with biological samples from participants who consented to multiomic analysis. PARTICIPANTS: NICOLA recruited 8478 participants (8283 aged 50 years or older and 195 spouses or partners at the same address aged under 50 years). Computer-Assisted Personal Interviews, Self-Completion Questionnaires and detailed Health Assessments (HA) were completed. Of the 3471 (44.1%) participants who attended the HA in wave 1, which included venous blood sampling, 2000 were identified for the DNAm cohort. Following technical and data quality control checks, DNAm data are currently available for n=1870. FINDINGS TO DATE: There was no significant difference based on age, self-reported gender, education, employment, smoking or alcohol status and subjective health reports between the DNAm cohort and other HA attendees. Participants were more likely to be in the DNAm group if they lived with one other person (OR 1.26, 95% CI 1.07 to 1.49). The DNAm group had a lower proportion of depressed participants and those meeting criteria for post-traumatic stress disorder (11.7% and 4.4% vs 13.5% and 4.5%, respectively) categorised by objective assessment tools but this was not significant (OR 0.84, 95% CI 0.69 to 1.02 and OR 0.87, 95% CI 0.64 to 1.19). FUTURE PLANS: The deeply phenotyped DNAm cohort in NICOLA with planned prospective follow-up and additional multiomic data releases will increase the cohort's utility for research into ageing. The genomic and epigenetic data for the DNAm cohort has been deposited on the European Genome-Phenome Archive, increasing the profile of this cohort and data availability to researchers.