title: Dynamic Myofibrillar Remodeling in Live Cardiomyocytes under Static Stretch.
abstract: An increase in mechanical load in the heart causes cardiac hypertrophy, either physiologically (heart development, exercise and pregnancy) or pathologically (high blood pressure and heart-valve regurgitation). Understanding cardiac hypertrophy is critical to comprehending the mechanisms of heart development and treatment of heart disease. However, the major molecular event that occurs during physiological or pathological hypertrophy is the dynamic process of sarcomeric addition, and it has not been observed. In this study, a custom-built second harmonic generation (SHG) confocal microscope was used to study dynamic sarcomeric addition in single neonatal CMs in a 3D culture system under acute, uniaxial, static, sustained stretch. Here we report, for the first time, live-cell observations of various modes of dynamic sarcomeric addition (and how these real-time images compare to static images from hypertrophic hearts reported in the literature): 1) Insertion in the mid-region or addition at the end of a myofibril; 2) Sequential addition with an existing myofibril as a template; and 3) Longitudinal splitting of an existing myofibril. The 3D cell culture system developed on a deformable substrate affixed to a stretcher and the SHG live-cell imaging technique are unique tools for real-time analysis of cultured models of hypertrophy.
authors: Department of Bioengineering, Clemson University, Clemson, SC, USA.
authors: Huaxiao
authors: H
authors: Yang
authors: Department of Bioengineering, Clemson University, Clemson, SC, USA.
authors: Lucas P
authors: LP
authors: Schmidt
authors: Department of Bioengineering, Clemson University, Clemson, SC, USA.
authors: Zhonghai
authors: Z
authors: Wang
authors: Department of Bioengineering, Clemson University, Clemson, SC, USA.
authors: Xiaoqi
authors: X
authors: Yang
authors: Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China.
authors: Yonghong
authors: Y
authors: Shao
authors: Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA.
authors: Thomas K
authors: TK
authors: Borg
authors: Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA.
authors: Roger
authors: R
authors: Markwald
authors: Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA.
authors: Raymond
authors: R
authors: Runyan
authors: Department of Bioengineering, Clemson University, Clemson, SC, USA.
authors: Bruce Z
authors: BZ
authors: Gao
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D016000:Cluster Analysis; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D009210:Myofibrils / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012518:Sarcomeres / Q000502:physiology; D013314:Stress, Mechanical