Effect of CM-Specific SMAD4 Deletion on CM Contraction Kinetics and on Contractility-Regulating Proteins
CMs were isolated from the hearts of experimental mice at the end of each time point and sarcomere shortening parameters assessed (n = 10 to 20 CMs/heart and 8 to 9 hearts/group). (A) Sarcomere peak shortening normalized to resting sarcomere length (% peak shortening). *p = 0.0104, **p = 0.0033 versus CTL group. (B) Maximal relengthening (+dL/dT) velocity. *p = 0.0101, **p = 0.0035. (C) Maximal shortening (–dL/dT) velocity. *p = 0.0102, **p = 0.0041. Western blot analysis of proteins that regulate calcium homeostasis and cardiomyocyte contractility. Representative Western blots and quantification. (D) Phospholamban (PLN). **p = 0.0099. (E) Sarco/endoplasmic reticulum Ca2+-ATPase 2a (SERCA2a). (F) Cardiac myosin binding protein C (cMyBP-C). *p = 0.0317. All p values are versus the CTL group. Abbreviations as in Figures 1 to 3.