Large scale, unbiased analysis of elementary calcium signaling events in cardiac myocytes

• Published in: Journal of molecular and cellular cardiology Vol. 135; pp. 79 - 89
• Main Authors: Tian, Qinghai, Schröder, Laura, Schwarz, Yvonne, Flockerzi, Aline, Kaestner, Lars, Zeug, Andre, Bruns, Dieter, Lipp, Peter
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2019
• Subjects: Active RyR cluster registration; Analysis algorithm; Ca2+ spark; Cardiac hypertrophy; Ultrafast 2D confocal scanning; Cardiac hypertrophy; Active RyR cluster registration; Ultrafast 2D confocal scanning; Ca2+ spark; Analysis algorithm; Ca(2+) spark
• ISSN: 0022-2828; 1095-8584
• DOI: 10.1016/j.yjmcc.2019.08.004

The identification of spatiotemporally restricted Ca2+ signals, Ca2+ sparks, was instrumental for our understanding of cardiac Ca2+ homeostasis. High-speed 2D confocal imaging enables acquisition of such Ca2+ sparks with high-content information but their full appreciation is constrained by the lack of unbiased and easy-to-use analysis tools. We developed a software toolset for unbiased and automatic Ca2+ spark analysis for huge data sets of subcellular Ca2+ signals. iSpark was developed to be scanner and detector independent. In myocytes from hearts subjected to various degrees of hypertrophy we acquired >5.000.000 Ca2+ sparks from 14 mice. The iSpark-enabled analysis of this large Ca2+ spark data set showed that the highly organized distribution of Ca2+ sparks present in healthy cells disarrayed concomitant with the development of aberrant transverse tubules and disease severity. Thus, iSpark represents a versatile and universal tool for analyzing local Ca2+ signaling in healthy as well as diseased, aberrant local Ca2+ signal transduction. The results from the unbiased analysis of large data sets provide a deeper insight into possible mechanisms contributing to the onset and progression of cardiac diseases such as hypertrophy. •iSpark for unbiased, automatic analysis of large scale 2D over time Ca2+ spark data.•autonomous 2D assignment of Ca2+ sparks to RyR clusters.•in myocytes from hypertrophied hearts we analyzed >5.000.000 Ca2+ sparks.•the Ca2+ spark amplitude correlates with the degree of cardiac hypertrophy.•the Ca2+ spark and T-tubular disarray correlate with the degree of cardiac hypertrophy.