Figure 2
Effects of individual ionic remodeling targets on the cytosolic calcium concentration ([Ca2+]i) and action potential (AP). (a) Characteristics of control atrial cells with each TBX5-remodeled cellular component i.e., fast sodium current, INa; transient outward potassium current, Ito; ultrarapid delayed rectifier potassium current, IKur; calcium flow through the sarcoplasmic reticulum calcium ATPase (SERCA), Jup, calcium flow through the ryanodine receptor (RyR), Jrel and inward rectifier potassium current, IK1, respectively. Spontaneous depolarizations are induced in human atrial cells with the remodeled IK1. AP prolongation, diastolic calcium elevation and increase in resting membrane potential (RMP) occur in human atrial cells with remodeled IKur, Jup and IK1, respectively. (b–d) Diastolic calcium concentration (Cadiast), RMP and action potential duration (APD90) for all cell variants are compared to control atrial myocytes (red bar). Main components which contribute to AP abnormalities in Hom-Tbx5 atrial cells are marked with red rectangles. Biomarkers of spontaneous depolarizations are marked with stars.
