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A screening campaign in sea urchin egg homogenate as a platform for discovering modulators of NAADP-dependent Ca2+ signaling in human cells. Cell Calcium 2018 11;75:42-52



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Scopus ID

2-s2.0-85051976642   8 Citations


The Ca2+ mobilizing second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) regulates intracellular trafficking events, including translocation of certain enveloped viruses through the endolysosomal system. Targeting NAADP-evoked Ca2+ signaling may therefore be an effective strategy for discovering novel antivirals as well as therapeutics for other disorders. To aid discovery of novel scaffolds that modulate NAADP-evoked Ca2+ signaling in human cells, we have investigated the potential of using the sea urchin egg homogenate system for a screening campaign. Known pharmacological inhibitors of NAADP-evoked Ca2+ release (but not cADPR- or IP3-evoked Ca2+ release) in this invertebrate system strongly correlated with inhibition of MERS-pseudovirus infectivity in a human cell line. A primary screen of 1534 compounds yielded eighteen 'hits' exhibiting >80% inhibition of NAADP-evoked Ca2+ release. A validation pipeline for these candidates yielded seven drugs that inhibited NAADP-evoked Ca2+ release without depleting acidic Ca2+ stores in a human cell line. These candidates displayed a similar penetrance of inhibition in both the sea urchin system and the human cell line, and the extent of inhibition of NAADP-evoked Ca2+ signals correlated well with observed inhibition of infectivity of a Middle East Respiratory syndrome coronavirus (MERS-CoV) pseudovirus. These experiments support the potential of this simple, homogenate system for screening campaigns to discover modulators of NAADP, cADPR and IP3-dependent Ca2+ signaling with potential therapeutic value.

Author List

Gunaratne GS, Johns ME, Hintz HM, Walseth TF, Marchant JS


Jonathan S. Marchant PhD Chair, Professor in the Cell Biology, Neurobiology and Anatomy department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Calcium Signaling
Cell Line
Drug Evaluation, Preclinical
Reproducibility of Results
Sea Urchins
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a