Loading...
EFFECTS OF LAMINAR SHEAR STRESS ON MITOCHONDRIAL DNA INTEGRITY IN ENDOTHELIAL CELLS
Kim, Boa
Kim, Boa
Citations
Altmetric:
Genre
Thesis/Dissertation
Date
2014
Advisor
Park, Joon Young
Committee member
Group
Department
Kinesiology
Permanent link to this record
Collections
Research Projects
Organizational Units
Journal Issue
DOI
http://dx.doi.org/10.34944/dspace/3093
Abstract
Purpose/hypothesis: Regular practice of exercise is the most effective non-pharmacological intervention that improves vascular health, which is thought to be mediated by a repeated exposure of vessel walls to increased hemodynamic shear stress (SS). Mitochondria have been shown to be essential cellular structures responsible for a wide variety of vascular functions, and its impairment is often associated with cardiovascular disease. However, researches on vascular mitochondrial adaptations to SS are in a very early stage and many questions remain unresolved. The objective of this study is to investigate the effect of exercise preconditioning on endothelial mitochondria in an angiotensin (Ang) II-induced hypertension model. It was hypothesized that exercise preconditioning prevents Ang II induced-hypertensive phenotypes by improving mitochondrial homeostasis in the endothelium. Methods: High-magnitude laminar SS (LSS) (20 dyne/cm2) was applied to human aortic endothelial cells (HAECs) using a cone-and-plate shear apparatus for 48 hours. Either LSS-preconditioned or static flow-situated HAECs were incubated with Ang II. In in vivo experiments, C57BL/6J mice were singly housed with or without a voluntary running wheel for 7 weeks. Ang II or saline was infused in a constant rate using an implantable osmotic pump for the last 2 weeks of the experimental period. Mitochondrial membrane potential (ÄØm) and mitoROS production were measured using fluorochrome molecular probe-based microscopic techniques, and mtDNA damage was assessed by a long amplicon quantitative PCR (LA-QPCR) method. Results: In HAECs, LSS preconditioning attenuated Ang II-induced mitochondrial dysfunction, which was evidenced by decreased mitoROS generation, increased ÄØm, and reduced mtDNA damage. Likewise, in aortic tissues, Ang II-induced mitochondrial phenotypic changes (i.e. mitoROS production, mtDNA damage and ÄØm reduction) were significantly reduced in exercise-preconditioned mice compared to sedentary controls. Moreover, Ang II-induced blood pressure elevation was completely blocked in exercise preconditioned animals. Conclusion: Taken together, high-magnitude LSS improves endothelial function by enhancing mtDNA integrity and mitochondrial function. These findings further support the idea that aerobic exercise is a prominent life-style modification strategy to prevent hypertension by targeting dysfunctional mitochondria in the vessel wall.
Description
Citation
Citation to related work
Has part
ADA compliance
For Americans with Disabilities Act (ADA) accommodation, including help with reading this content, please contact scholarshare@temple.edu