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Mining of Ebola virus entry inhibitors identifies approved drugs as two-pore channel pore blockers.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Penny, Christopher J 
Vassileva, Kristin 
Jha, Archana 
Yuan, Yu 
Chee, Xavier 

Abstract

Two-pore channels (TPCs) are Ca2+-permeable ion channels localised to the endo-lysosomal system where they regulate trafficking of various cargoes including viruses. As a result, TPCs are emerging as important drug targets. However, their pharmacology is ill-defined. There are no approved drugs to target them. And their mechanism of ligand activation is largely unknown. Here, we identify a number of FDA-approved drugs as TPC pore blockers. Using a model of the pore of human TPC2 based on recent structures of mammalian TPCs, we virtually screened a database of ~1500 approved drugs. Because TPCs have recently emerged as novel host factors for Ebola virus entry, we reasoned that Ebola virus entry inhibitors may exert their effects through inhibition of TPCs. Cross-referencing hits from the TPC virtual screen with two recent high throughput anti-Ebola screens yielded approved drugs targeting dopamine and estrogen receptors as common hits. These compounds inhibited endogenous NAADP-evoked Ca2+ release from sea urchin egg homogenates, NAADP-mediated channel activity of TPC2 re-routed to the plasma membrane, and PI(3,5)P2-mediated channel activity of TPC2 expressed in enlarged lysosomes. Mechanistically, single channel analyses showed that the drugs reduced mean open time consistent with a direct action on the pore. Functionally, drug potency in blocking TPC2 activity correlated with inhibition of Ebola virus-like particle entry. Our results expand TPC pharmacology through the identification of approved drugs as novel blockers, support a role for TPCs in Ebola virus entry, and provide insight into the mechanisms underlying channel regulation. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.

Description

Keywords

Ca(2+), Ebola virus, Lysosomes, NAADP, TPC2, Virtual screening, Animals, Antiviral Agents, Calcium Channels, Drug Evaluation, Ebolavirus, HEK293 Cells, Humans, Lysosomes, Phosphatidylinositol Phosphates, Sea Urchins, Virus Internalization

Journal Title

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

Conference Name

Journal ISSN

0167-4889
1879-2596

Volume Title

1866

Publisher

Elsevier

Rights

All rights reserved