Aggresomes are dynamic structures formed when the ubiquitin-proteasome system is overwhelmed with aggregation-prone proteins. In this process, small protein aggregates are actively transported towards the microtubule-organizing center. A functional role for autophagy in the clearance of aggresomes has also been proposed. In the present work we investigated the molecular mechanisms involved on aggresome formation in cultured rat cardiac myocytes exposed to glucose deprivation. Confocal microscopy showed that small aggregates of polyubiquitinated proteins were formed in cells exposed to glucose deprivation for 6 h. However, at longer times (18 h), aggregates formed large perinuclear inclusions (aggresomes) which colocalized with gamma-tubulin (a microtubule-organizing center marker) and Hsp70. The microtubule disrupting agent vinblastine prevented the formation of these inclusions. Both small aggregates and aggresomes colocalized with autophagy markers such as GFP-LC3 and Rab24. Glucose deprivation stimulates reactive oxygen species (ROS) production and decreases intracellular glutathione levels. ROS inhibition by N-acetylcysteine or by the adenoviral overexpression of catalase or superoxide dismutase disrupted aggresome formation and autophagy induced by glucose deprivation. In conclusion, glucose deprivation induces oxidative stress which is associated with aggresome formation and activation of autophagy in cultured cardiac myocytes.

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We developed and pilot tested the effectiveness of a physically active academic program, Active Breaks (AB), whose objective is to increase school time moderate/vigorous physical activity (MVPA) among first graders, through daily 15-minute bouts of MVPA, at the beginning of the first lesson. Initially, 240 cards including one game each were developed and tested in first-grade students from 16 schools in Santiago. Trained observers and school teachers assessed the time, ease, and feasibility of implementation for each card. Barriers and facilitators to implementation were obtained from semistructured interviews to 14 teachers (out of 16). In eight schools ( n = 556 students), we compared school time MVPA (with accelerometers) at baseline and follow-up, using test of proportions. One-hundred and twenty cards (games) complied with all aspects. AB were implemented 50% of the time with a duration of 14 minutes ( SD = 5). More than 90% of the time, teachers felt competent to conduct AB, and children understood the instructions and enjoyed the activity. The main facilitators included teachers liking physical activity and considering it important, support of principal and school staff, and conducting AB inside the classroom. Barriers included teacher’s workload and having to conduct AB during the first lesson. During the 4-month period of implementation, MVPA increased by 1.5 and 1.2 percentage points in boys and girls, respectively. The set of 120 cards is easy and feasible to implement. Moreover, preliminary results suggest they could be effective in increasing MVPA during school time, although studies with longer follow-ups are needed to assess the validity of these findings.