Mechanism of cardiac remodeling using a three-dimensional culture model

Cardiac myocytes respond to fluctuating patterns of activity and load by remodeling to operate more efficiently. The cardiac remodeling events are represented by either hypertrophy, or atrophy, of the cardiac myocyte. Our study focused on determining the mechanism of cardiac remodeling as it occurs in hypertrophy. Our model utilized a static strain system composed of pegs to provide for improved cell attachment, and grooves to align the cells.;Cardiac myocytes were grown on laminin coated silicone membranes consisting of either a textured, or untextured surface. To monitor the mechanism of cardiac remodeling we have established an assay to measure the sarcomere length of individual myocytes before and after strain. After an immediate strain of 10%, the sarcomere length of cells grown on the flat surface were not significantly longer, while the sarcomere lengths in cardiac myocytes grown on textured surfaces were longer and returned to their rest length by 4 hours after being strained 10%.;The sarcomere length of the strained cardiac myocytes did not return to their original resting length by 4 hours with puromycin (10μM) treatment indicating that protein synthesis is required for cardiac resting sarcomere length recovery after strain.;Recent evidence has illustrated that two proteins, protein kinase Cϵ (PKCϵ) and focal adhesion kinase (FAK), are involved in mechanical signal transduction within cardiac mycoytes. We chose to investigate their roles utilizing novel adenoviral constructs during cardiac remodeling. By using non-specific inhibitors to PKC and a dominant-negative PKC epsilon adenovrial construct, as well as a non-phosphorylatable form of focal adhesion kinase, we were able to determine the important role of PKC and FAK in sarcomere length remodeling.;In conclusion, the textured surface provides aligned, well attached cardiac myocytes for our strain experiments. We were able to accurately determine the recovery time of the resting sarcomere length using the textured surface, as well as the role of protein synthesis. We were also able to determine that PKC and FAK participate in the mechanical signaling pathway for cellular adaptation to uniaxial strain.