Synchronization of Circadian Per2 Rhythms and HSF1-BMAL1:CLOCK Interaction in Mouse Fibroblasts after Short-Term Heat Shock Pulse

Circadian rhythms are the general physiological processes of adaptation to daily environmental changes, such as the temperature cycle. A change in temperature is a resetting cue for mammalian circadian oscillators, which are possibly regulated by the heat shock (HS) pathway. The HS response (HSR) is a universal process that provides protection against stressful conditions, which promote protein-denaturation. Heat shock factor 1 (HSF1) is essential for HSR. In the study presented here, we investigated whether a short-term HS pulse can reset circadian rhythms. Circadian Per2 rhythm and HSF1-mediated gene expression were monitored by a real-time bioluminescence assay for mPer2 promoter-driven luciferase and HS element (HSE; HSF1-binding site)-driven luciferase activity, respectively. By an optimal duration HS pulse (43°C for approximately 30 minutes), circadian Per2 rhythm was observed in the whole mouse fibroblast culture, probably indicating the synchronization of the phases of each cell. This rhythm was preceded by an acute elevation in mPer2 and HSF1-mediated gene expression. Mutations in the two predicted HSE sites adjacent (one of them proximally) to the E-box in the mPer2 promoter dramatically abolished circadian mPer2 rhythm. Circadian Per2 gene/protein expression was not observed in HSF1-deficient cells. These findings demonstrate that HSF1 is essential to the synchronization of circadian rhythms by the HS pulse. Importantly, the interaction between HSF1 and BMAL1:CLOCK heterodimer, a central circadian transcription factor, was observed after the HS pulse. These findings reveal that even a short-term HS pulse can reset circadian rhythms and cause the HSF1-BMAL1:CLOCK interaction, suggesting the pivotal role of crosstalk between the mammalian circadian and HSR systems

A mathematical model of aging-related and cortisol induced hippocampal dysfunction

<p>Abstract</p> <p>Background</p> <p>The hippocampus is essential for declarative memory synthesis and is a core pathological substrate for Alzheimer's disease (AD), the most common aging-related dementing disease. Acute increases in plasma cortisol are associated with transient hippocampal inhibition and retrograde amnesia, while chronic cortisol elevation is associated with hippocampal atrophy. Thus, cortisol levels could be monitored and managed in older people, to decrease their risk of AD type hippocampal dysfunction. We generated an in silico<it/>model of the chronic effects of elevated plasma cortisol on hippocampal activity and atrophy, using the systems biology mark-up language (SBML). We further challenged the model with biologically based interventions to ascertain if cortisol associated hippocampal dysfunction could be abrogated.</p> <p>Results</p> <p>The in silico<it/>SBML model reflected the in vivo<it/>aging of the hippocampus and increased plasma cortisol and negative feedback to the hypothalamic pituitary axis. Aging induced a 12% decrease in hippocampus activity (HA), increased to 30% by acute and 40% by chronic elevations in cortisol. The biological intervention attenuated the cortisol associated decrease in HA by 2% in the acute cortisol simulation and by 8% in the chronic simulation.</p> <p>Conclusion</p> <p>Both acute and chronic elevations in cortisol secretion increased aging-associated hippocampal atrophy and a loss of HA in the model. We suggest that this first SMBL model, in tandem with in vitro<it/>and in vivo<it/>studies, may provide a backbone to further frame computational cortisol and brain aging models, which may help predict aging-related brain changes in vulnerable older people.</p

PREPARATION ET PROPRIETES DU BENZOATE DE VINYLE

(Docteur en Sciences) -- Université catholique de Louvain, 195

Violence à l'adolescence, porteuse d'un diagnostic familial et culturel. La violence juvénile à El Alto

Master [120] en criminologie, Université catholique de Louvain, 201

Die Rolle der Schilddrüse bei Stillstand und Hemmung des Wachstums und der Entwicklung und der chronische gutartige Hypothyreoidismus.

Mode of access: Internet

How can influencers change consumer behavior in sustainable consumption

The aim of the research is to investigate the strategies influencers should adopt to drive actual change towards sustainable consumption habits. The research was done through qualitative research methods through eighteen interviews from three different samples: social media influencers, customers, and marketing directors. The key findings are that authenticity, transparency, proximity, and credibility are crucial. The value of time, price, facts, and numbers are also key in convincing followers to purchase sustainable offerings. Content formats and the way of presenting brands are also playing a role in the ability to influence change. Influencers should consider this when addressing their audience