Hypoxia-Induced Down-Regulation of Neprilysin by Histone Modification in Mouse Primary Cortical and Hippocampal Neurons

Amyloid β-peptide (Aβ) accumulation leads to neurodegeneration and Alzheimer's disease (AD). Aβ metabolism is a dynamic process in the Aβ production and clearance that requires neprilysin (NEP) and other enzymes to degrade Aβ. It has been reported that NEP expression is significantly decreased in the brain of AD patients. Previously we have documented hypoxia is a risk factor for Aβ generation in vivo and in vitro through increasing Aβ generation by altering β-cleavage and γ-cleavage of APP and down-regulating NEP, and causing tau hyperphosphorylation. Here, we investigated the molecular mechanisms of hypoxia-induced down-regulation of NEP. We found a significant decrease in NEP expression at the mRNA and protein levels after hypoxic treatment in mouse primary cortical and hippocampal neurons. Chromatin immunoprecipitation (ChIP) assays and relative quantitative PCR (q-PCR) revealed an increase of histone H3-lysine9 demethylation (H3K9me2) and a decrease of H3 acetylation (H3-Ace) in the NEP promoter regions following hypoxia. In addition, we found that hypoxia caused up-regulation of histone methyl transferase (HMT) G9a and histone deacetylases (HDACs) HDAC-1. Decreased expression of NEP during hypoxia can be prevented by application with the epigenetic regulators 5-Aza-2′-deoxycytidine (5-Aza), HDACs inhibitor sodium valproate (VA), and siRNA-mediated knockdown of G9a or HDAC1. DNA methylation PCR data do not support that hypoxia affects the methylation of NEP promoters. This study suggests that hypoxia may down-regulate NEP by increasing H3K9me2 and decreasing H3-Ace modulation

Regulation of Spike Timing-Dependent Plasticity of Olfactory Inputs in Mitral Cells in the Rat Olfactory Bulb

The recent history of activity input onto granule cells (GCs) in the main olfactory bulb can affect the strength of lateral inhibition, which functions to generate contrast enhancement. However, at the plasticity level, it is unknown whether and how the prior modification of lateral inhibition modulates the subsequent induction of long-lasting changes of the excitatory olfactory nerve (ON) inputs to mitral cells (MCs). Here we found that the repetitive stimulation of two distinct excitatory inputs to the GCs induced a persistent modification of lateral inhibition in MCs in opposing directions. This bidirectional modification of inhibitory inputs differentially regulated the subsequent synaptic plasticity of the excitatory ON inputs to the MCs, which was induced by the repetitive pairing of excitatory postsynaptic potentials (EPSPs) with postsynaptic bursts. The regulation of spike timing-dependent plasticity (STDP) was achieved by the regulation of the inter-spike-interval (ISI) of the postsynaptic bursts. This novel form of inhibition-dependent regulation of plasticity may contribute to the encoding or processing of olfactory information in the olfactory bulb

Consensus guidelines for the use and interpretation of angiogenesis assays

The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference

Situação-problema como disparador do processo de ensino-aprendizagem em metodologias ativas de ensino

RESUMO: Objetivo: descrever o processo de elaboração de uma Situação-Problema e de um Módulo de aprendizagem e refletir a importância destes na formação do Fonoaudiólogo. Métodos: estudo descritivo do processo de elaboração de uma Situação-Problema e de um Módulo de aprendizagem de um curso de graduação em Fonoaudiologia - uma experiência precursora na área em que toda a estrutura curricular tem como base Metodologias Ativas de ensino. Resultado: o Módulo Estudo da Linguagem Infantil ocorre no Ciclo II do Curso e é constituído por nove Situações-Problema sendo, cada uma, discutida em duas sessões tutoriais com até dez discentes e conduzida por um professor tutor. As Situações-Problema, assim como o Módulo, são elaboradas por uma comissão de docentes doutores e especialistas em Linguagem de acordo com o Projeto Pedagógico do Curso. Discute-se, neste artigo, a terceira Situação-Problema que tem como título - "Mesmas características, mas diagnósticos diferentes... Por quê?"; O título tem o papel de despertar a curiosidade do discente e apresentar o enfoque principal do problema. Todas as Situações-Problema são avaliadas por docentes e discentes com objetivo de promover aperfeiçoamentos constantes. Conclusão: o contexto problematizador construído a partir das Situações-Problema permite ao discente a busca de respostas diariamente, de forma ativa e autônoma, pela vivência e discussão do trabalho em equipe, dos aspectos biopsicossociais do indivíduo e das questões éticas na atuação profissional. Possibilitando assim a formação de profissionais resolutivos, competentes para aperfeiçoar seu conhecimento constantemente e de atuar em consonância com as práticas de Saúde Pública do País