Arterial stiffening accompanies both aging and atherosclerosis, and age-related stiffening of the arterial intima increases RhoA activity and cell contractility contributing to increased endothelium permeability. Notably, statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors whose pleiotropic effects include disrupting small GTPase activity; therefore, we hypothesized the statin simvastatin could be used to attenuate RhoA activity and inhibit the deleterious effects of increased age-related matrix stiffness on endothelial barrier function. Using polyacrylamide gels with stiffnesses of 2.5, 5, and 10 kPa to mimic the physiological stiffness of young and aged arteries, endothelial cells were grown to confluence and treated with simvastatin. Our data indicate that RhoA and phosphorylated myosin light chain activity increase with matrix stiffness but are attenuated when treated with the statin. Increases in cell contractility, cell-cell junction size, and indirect measurements of intercellular tension that increase with matrix stiffness, and are correlated with matrix stiffness-dependent increases in monolayer permeability, also decrease with statin treatment. Furthermore, we report that simvastatin increases activated Rac1 levels that contribute to endothelial barrier enhancing cytoskeletal reorganization. Simvastatin, which is prescribed clinically due to its ability to lower cholesterol, alters the endothelial cell response to increased matrix stiffness to restore endothelial monolayer barrier function, and therefore, presents a possible therapeutic intervention to prevent atherogenesis initiated by age-related arterial stiffening.
1 October 2017 in Journal of Engineering Education
Background: Participating in undergraduate research experiences (UREs) supports the development of engineering students' technical and professional skills. However, little is known about the perceptions of research or researchers that students develop through these experiences. Understanding these perceptions will provide insight into how students come to understand knowledge evaluation and creation, while allowing research advisors to better support student development.Purpose: In this paper, we explore how undergraduate engineering students perceive what it means to do research and be a researcher, using identity and epistemic cognition as sensitizing concepts. Our goal is to explore students' views of UREs to make the benefits of these experiences more accessible.Design/Method: We created and adapted open‐ended survey items from previously published studies. We collected responses from mechanical and biomedical engineering undergraduates at five institutions (n= 154) and used an inductive approach to analyze responses.Results: We developed four salient themes from our analysis: (a) research results in discovery, (b) research includes dissemination such as authorship, (c) research findings are integrated into society, and (d) researchers demonstrate self‐regulation.Conclusions: The four themes highlight factors that students perceive as part of a researcher identity and aspects of epistemic cognition in the context of UREs. These results suggest structuring UREs to provide opportunities for discovery, dissemination, societal impact, and self‐regulation will help support students in their development as researchers.
25 November 2021 in Journal of Research in Science Teaching
This study examined the teachers' development as scientists for participants in three National Science Foundation Research Experiences for Teachers. Participants included secondary science and math teachers with varying levels of education and experience who were immersed in research environments related to engineering and science topics. Teachers’ functionality as scientists was assessed in terms of independence, focus, relationships with mentors, structure, and ability to create new concepts. Hierarchies developed within these constructs allowed tracking of changes in functionality throughout the 6-week programs. Themes were further identified in teachers’ weekly journal entries and exit interviews through inductive coding. Increases in functionality as scientists were observed for all teachers who completed both the program and exit interview (n = 27). Seven of the 27 teachers reached high science functionality; however, three of the teachers did not reach high functionality in any of the constructs during the program. No differences were observed in demographics or teaching experience between those who did and did not reach high functionality levels. Inductive coding revealed themes such as teachers’ interactions with mentors and connections made between research and teaching, which allowed for descriptions of experiences for teachers at high and low levels of functionality. Teachers at high functionality levels adjusted to open-ended environments, transitioned from a guided experience to freedom, felt useful in the laboratory, and were self-motivated. In contrast, teachers at low functionality levels did not have a true research project, primarily focused on teaching aspects of the program, and did not display a transition of responsibilities.