Rotavirus Calcium Dysregulation Manifests as Dynamic Calcium Signaling in the Cytoplasm and Endoplasmic Reticulum

• Published in: Scientific reports Vol. 9; no. 1; pp. 10822 - 20
• Main Authors: Chang-Graham, Alexandra L, Perry, Jacob L, Strtak, Alicia C, Ramachandran, Nina K, Criglar, Jeanette M, Philip, Asha A, Patton, John T, Estes, Mary K, Hyser, Joseph M
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 25.07.2019; Nature Publishing Group UK
• Subjects: Calcium (reticular); Calcium - metabolism; Calcium channels; Calcium homeostasis; Calcium Signaling - physiology; Calcium signalling; Cell Line; Cell lines; Cytoplasm; Cytoplasm - metabolism; Endoplasmic reticulum; Endoplasmic Reticulum - metabolism; Homeostasis; Humans; Infections; Intestine; Orai1 protein; Rotavirus; Rotavirus - metabolism; Rotavirus Infections - metabolism; Viruses
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-46856-8

Like many viruses, rotavirus (RV) dysregulates calcium homeostasis by elevating cytosolic calcium ([Ca ]cyt) and decreasing endoplasmic reticulum (ER) stores. While an overall, monophasic increase in [Ca ]cyt during RV infection has been shown, the nature of the RV-induced aberrant calcium signals and how they manifest over time at the single-cell level have not been characterized. Thus, we generated cell lines and human intestinal enteroids (HIEs) stably expressing cytosolic and/or ER-targeted genetically-encoded calcium indicators to characterize calcium signaling throughout RV infection by time-lapse imaging. We found that RV induces highly dynamic [Ca ]cyt signaling that manifest as hundreds of discrete [Ca ]cyt spikes, which increase during peak infection. Knockdown of nonstructural protein 4 (NSP4) attenuates the [Ca ]cyt spikes, consistent with its role in dysregulating calcium homeostasis. RV-induced [Ca ]cyt spikes were primarily from ER calcium release and were attenuated by inhibiting the store-operated calcium entry (SOCE) channel Orai1. RV-infected HIEs also exhibited prominent [Ca ]cyt spikes that were attenuated by inhibiting SOCE, underlining the relevance of these [Ca ]cyt spikes to gastrointestinal physiology and role of SOCE in RV pathophysiology. Thus, our discovery that RV increases [Ca ]cyt by dynamic calcium signaling, establishes a new, paradigm-shifting understanding of the spatial and temporal complexity of virus-induced calcium signaling.