Ezrin Is Highly Expressed in Early Thymocytes, but Dispensable for T Cell Development in Mice

Ezrin/radixin/moesin (ERM) proteins are highly homologous proteins that function to link cargo molecules to the actin cytoskeleton. Ezrin and moesin are both expressed in mature lymphocytes, where they play overlapping roles in cell signaling and polarity, but their role in lymphoid development has not been explored.We characterized ERM protein expression in lymphoid tissues and analyzed the requirement for ezrin expression in lymphoid development. In wildtype mice, we found that most cells in the spleen and thymus express both ezrin and moesin, but little radixin. ERM protein expression in the thymus was differentially regulated, such that ezrin expression was highest in immature thymocytes and diminished during T cell development. In contrast, moesin expression was low in early thymocytes and upregulated during T cell development. Mice bearing a germline deletion of ezrin exhibited profound defects in the size and cellularity of the spleen and thymus, abnormal thymic architecture, diminished hematopoiesis, and increased proportions of granulocytic precursors. Further analysis using fetal liver chimeras and thymic transplants showed that ezrin expression is dispensable in hematopoietic and stromal lineages, and that most of the defects in lymphoid development in ezrin(-/-) mice likely arise as a consequence of nutritional stress.We conclude that despite high expression in lymphoid precursor cells, ezrin is dispensable for lymphoid development, most likely due to redundancy with moesin

Impact of a school-level intervention on leisure-time physical activity levels on school grounds in under-resourced school districts

Even the best school physical education programs fall short of providing enough physical activity (PA) to meet students’ PA guidelines thus increasing PA at other times throughout the school day could help students meet recommended PA levels. Unstructured leisure-time periods during the school day represent an opportunity to promote PA, particularly among students in underserved school districts. Between 2014 and 2018, we partnered with 14 elementary and 5 secondary schools in low-income Latino communities to increase students’ leisure time moderate to vigorous physical activity (MVPA). Schools received consultation and technical assistance on their wellness policy, and some created wellness committees. Schools selected 1–2 PA/nutrition promotion activities for the academic year. Following the System for Observing Play and Leisure Activity in Youth protocol, we conducted a pre- vs. post- analysis of observations of school time student PA (levels of MVPA, energy expenditure, proportion of areas in which games and sports were prominent) in 4936 pre-intervention play areas and 4404 post-intervention areas before school, during lunch recess, and after school. We utilized linear and logistic regression analyses to test pre/post changes in these dependent variables using school area characteristics, period of observation, and temperature as covariates. Following our intervention, MVPA levels before school, during lunch recess, and after school increased significantly from 19.8% at baseline to 25.6% among elementary girls and from 25.4% to 33.2% among elementary boys. Decomposition of these effects suggested that the benefits were partially mediated by increased adult playground supervision. We did not observe any significant changes in PA levels among secondary school girls or boys. Our school-level intervention aimed at promoting PA was associated with modest but meaningful increases in leisure-time PA among elementary, but not secondary, school students. The effects were attributable in part to increased adult supervision on the playground

Reconsidering reviews: the role of scoping reviews in digital medicine and pediatrics

Digital health is a rapidly developing field which is positioned to transform the manner in which healthcare is delivered, especially amongst adolescents and young adults. In order to assess the efficacy of novel medical devices, clinicians and researchers often turn to the literature for guidance. Randomized control trials and the systematic reviews and meta-analyses that they inform are considered to be at the top of the evidence hierarchy. While they are excellent tools to identify and to summarize the best available evidence to answer a specific research question, they are poorly equipped to provide a more expansive understanding of the body of relevant literature in a timely manner. In this letter we discuss the utility of the scoping review, an underutilized style of academic writing designed to map key concepts in a body of literature. This method is ideal when reporting on the fast-paced field of digital medicine, as it allows for rapid synthesis of the available literature

Red seaweed (Asparagopsis taxiformis) supplementation reduces enteric methane by over 80 percent in beef steers.

The red macroalgae (seaweed) Asparagopsis spp. has shown to reduce ruminant enteric methane (CH4) production up to 99% in vitro. The objective of this study was to determine the effect of Asparagopsis taxiformis on CH4 production (g/day per animal), yield (g CH4/kg dry matter intake (DMI)), and intensity (g CH4/kg ADG); average daily gain (ADG; kg gain/day), feed conversion efficiency (FCE; kg ADG/kg DMI), and carcass and meat quality in growing beef steers. Twenty-one Angus-Hereford beef steers were randomly allocated to one of three treatment groups: 0% (Control), 0.25% (Low), and 0.5% (High) A. taxiformis inclusion based on organic matter intake. Steers were fed 3 diets: high, medium, and low forage total mixed ration (TMR) representing life-stage diets of growing beef steers. The Low and High treatments over 147 days reduced enteric CH4 yield 45 and 68%, respectively. However, there was an interaction between TMR type and the magnitude of CH4 yield reduction. Supplementing low forage TMR reduced CH4 yield 69.8% (P <0.01) for Low and 80% (P <0.01) for High treatments. Hydrogen (H2) yield (g H2/DMI) increased (P <0.01) 336 and 590% compared to Control for the Low and High treatments, respectively. Carbon dioxide (CO2) yield (g CO2/DMI) increased 13.7% between Control and High treatments (P = 0.03). No differences were found in ADG, carcass quality, strip loin proximate analysis and shear force, or consumer taste preferences. DMI tended to decrease 8% (P = 0.08) in the Low treatment and DMI decreased 14% (P <0.01) in the High treatment. Conversely, FCE tended to increase 7% in Low (P = 0.06) and increased 14% in High (P <0.01) treatment compared to Control. The persistent reduction of CH4 by A. taxiformis supplementation suggests that this is a viable feed additive to significantly decrease the carbon footprint of ruminant livestock and potentially increase production efficiency

Hippocampal replay of experience at real-world speeds.

Representations related to past experiences play a critical role in memory and decision-making processes. The rat hippocampus expresses these types of representations during sharp-wave ripple (SWR) events, and previous work identified a minority of SWRs that contain 'replay' of spatial trajectories at ∼20x the movement speed of the animal. Efforts to understand replay typically make multiple assumptions about which events to examine and what sorts of representations constitute replay. We therefore lack a clear understanding of both the prevalence and the range of representational dynamics associated with replay. Here, we develop a state space model that uses a combination of movement dynamics of different speeds to capture the spatial content and time evolution of replay during SWRs. Using this model, we find that the large majority of replay events contain spatially coherent, interpretable content. Furthermore, many events progress at real-world, rather than accelerated, movement speeds, consistent with actual experiences

Ezrin Is Highly Expressed in Early Thymocytes, but Dispensable for T Cell Development in Mice

Background: Ezrin/radixin/moesin (ERM) proteins are highly homologous proteins that function to link cargo molecules to the actin cytoskeleton. Ezrin and moesin are both expressed in mature lymphocytes, where they play overlapping roles in cell signaling and polarity, but their role in lymphoid development has not been explored.Methodology/Principal Findings: We characterized ERM protein expression in lymphoid tissues and analyzed the requirement for ezrin expression in lymphoid development. In wildtype mice, we found that most cells in the spleen and thymus express both ezrin and moesin, but little radixin. ERM protein expression in the thymus was differentially regulated, such that ezrin expression was highest in immature thymocytes and diminished during T cell development. In contrast, moesin expression was low in early thymocytes and upregulated during T cell development. Mice bearing a germline deletion of ezrin exhibited profound defects in the size and cellularity of the spleen and thymus, abnormal thymic architecture, diminished hematopoiesis, and increased proportions of granulocytic precursors. Further analysis using fetal liver chimeras and thymic transplants showed that ezrin expression is dispensable in hematopoietic and stromal lineages, and that most of the defects in lymphoid development in ezrin−/− mice likely arise as a consequence of nutritional stress.Conclusions/Significance: We conclude that despite high expression in lymphoid precursor cells, ezrin is dispensable for lymphoid development, most likely due to redundancy with moesin.</p