S100A1 in cardiovascular health and disease: Closing the gap between basic science and clinical therapy

Calcium (Ca²⁺) signaling plays a major role in a wide range of physiological functions including control and regulation of cardiac and skeletal muscle performance and vascular tone [1] and [2]. As all Ca²⁺ signals require proteins to relay intracellular Ca²⁺ oscillations downstream to different signaling networks, a specific toolkit of Ca²⁺-sensor proteins involving members of the EF-hand S100 Ca²⁺ binding protein superfamily maintains the integrity of the Ca²⁺ signaling in a variety of cardiac and vascular cells, transmitting the message with great precision and in a temporally and spatially coordinated manner [3], [4], [5] and [6]. Indeed, the possibility that S100 proteins might contribute to heart and vascular diseases was first suggested by the discovery of distinctive patterns of S100 expression in healthy and diseased hearts and vasculature from humans and animal heart failure (HF) models [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17] and [18]. Based on more elaborate genetic studies in mice and strategies to manipulate S100 protein expression in human cardiac, skeletal muscle and vascular cells, it is now apparent that the integrity of distinct S100 protein isoforms in striated muscle and vascular cells such as S100A1, S100A4, S100A6, S100A8/A9 or S100B is a basic requirement for normal cardiovascular and muscular development and function; loss of integrity would naturally lead to profound deregulation of the implicated Ca²⁺ signaling systems with detrimental consequences to cardiac, skeletal muscle, and vascular function [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19] and [20]. The brief debate and discussion here are confined by design to the biological actions and pathophysiological relevance of the EF-hand Ca²⁺-sensor protein S100A1 in the heart, vasculature and skeletal muscle with a particular focus on current translational therapeutic strategies [4], [21] and [23]. By virtue of its ability to modulate the activity of numerous key effector proteins that are essentially involved in the control of Ca²⁺ and NO homeostasis in cardiac, skeletal muscle and vascular cells, S100A1 has been proven to play a critical role both in cardiac performance, blood pressure regulation and skeletal muscle function [4,21,23]. Given that deregulated S100A1 expression in cardiomyocytes and endothelial cells has recently been linked to heart failure and hypertension [4,21,23], it is arguably a molecular target of considerable clinical interest as S100A1 targeted therapies have already been successfully investigated in preclinical translational studies.