Authors:

Kenneth David Siefken

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About Paper:

Intracellular calcium (Ca2+) signaling plays a vital role in coordinating tissue and organ-level responses to pathogens, wounding, and stress. These responses typically involve two phases: an initial Ca2+ signal and, in many cases, a subsequent wave-like propagation of Ca2+ across the tissue. In this work, we investigate how Ca2+-induced Ca2+ release (CICR) contributes to the propagation of these waves. Unlike previous models that treat tissue as a continuous medium, we develop a hybrid agent-based modeling framework that explicitly incorporates individual cell geometries and cell-cell communication mediated by gap junctions (GJ) in animals and plasmodesmata (PD) in plants. We also include a Ca2+-dependent sink to reflect physiological clearance mechanisms. In this study, we explore how varying model parameters influence the emergence of different Ca2+ wave patterns, including continuous waves, stop-and-go propagation, and complete failure of wave initiation. By performing systematic parameter screening using Latin Hypercube Sampling, we characterize how CICR-mediated signaling is regulated across different parameter regimes and how it affects wave speed and travel distance. We also focus on Ca2+-mediated regulation of cell-cell communication. Specifically, we examine how Ca2+ influences the closure of communication channels such as PD, known to be Ca2+- sensitive in Arabidopsis thaliana and other systems. We test three models of PD permeability: constant, linearly Ca2+-dependent, and biphasic. We quantify the diversity of resulting Ca2+ wave patterns using entropy calculations and compare these findings with alternative models of wave propagation. Together, this work advances our understanding of Ca2+ wave propagation and intercellular communication in response to external stimuli. Keywords: Calcium; Plasmodesmata; Wave Velocity; Computational Model; Intracellular Communication

Source:

Purdue University / 2025

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Co-authors:

Kenneth David Siefken