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Small Molecule Inhibitor Screen Reveals Calcium Channel Signaling as a Mechanistic Mediator of Clostridium difficile TcdB-Induced Necrosis
Version 2 2020-03-05, 18:21
Version 1 2020-01-14, 13:09
journal contribution
posted on 2020-03-05, 18:21 authored by Melissa
A. Farrow, Nicole M. Chumber, Sarah C. Bloch, McKenzie King, Kaycei Moton-Melancon, John Shupe, Mary K. Washington, Benjamin W. Spiller, D. Borden LacyClostridioides difficile is the leading cause
of nosocomial diarrhea in the United States. The primary virulence
factors are two homologous glucosyltransferase toxins, TcdA and TcdB,
that inactivate host Rho-family GTPases. The glucosyltransferase activity
has been linked to a “cytopathic” disruption of the
actin cytoskeleton and contributes to the disruption of tight junctions
and the production of pro-inflammatory cytokines. TcdB is also a potent
cytotoxin that causes epithelium necrotic damage through an NADPH
oxidase (NOX)-dependent mechanism. We conducted a small molecule screen
to identify compounds that confer protection against TcdB-induced
necrosis. We identified an enrichment of “hit compounds”
with a dihydropyridine (DHP) core which led to the discovery of a
key early stage calcium signal that serves as a mechanistic link between
TcdB-induced NOX activation and reactive oxygen species (ROS) production.
Disruption of TcdB-induced calcium signaling (with both DHP and non-DHP
molecules) is sufficient to ablate ROS production and prevent subsequent
necrosis in cells and in a mouse model of intoxication.
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Keywords
host Rho-family GTPasesnosocomial diarrheaTcdB-induced calciumglucosyltransferase toxinscompoundSmall Molecule Inhibitor Screenvirulence factorsCalcium Channel SignalingNADPH oxidasestage calcium signalUnited Statescauses epitheliumreactive oxygen speciesMechanistic MediatorTcdB-induced necrosisglucosyltransferase activitydisruptionmolecule screenTcdB-Induced Necrosis Clostridioidesmouse modelactin cytoskeletonnon-DHP moleculesablate ROS productionTcdB-induced NOX activationpro-inflammatory cytokines
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