title: Shiga toxin type-2 (Stx2) induces glutamate release via phosphoinositide 3-kinase (PI3K) pathway in murine neurons.
abstract: Shiga toxin-producing Escherichia coli (STEC) can cause central nervous system (CNS) damage resulting in paralysis, seizures, and coma. The key STEC virulence factors associated with systemic illness resulting in CNS impairment are Shiga toxins (Stx). While neurons express the Stx receptor globotriaosylceramide (Gb3) in vivo, direct toxicity to neurons by Stx has not been studied. We used murine neonatal neuron cultures to study the interaction of Shiga toxin type 2 (Stx2) with cell surface expressed Gb3. Single molecule imaging three dimensional STochastic Optical Reconstruction Microscopy-Total Internal Reflection Fluorescence (3D STORM-TIRF) allowed visualization and quantification of Stx2-Gb3 interactions. Furthermore, we demonstrate that Stx2 increases neuronal cytosolic Ca(2+), and NMDA-receptor inhibition blocks Stx2-induced Ca(2+) influx, suggesting that Stx2-mediates glutamate release. Phosphoinositide 3-kinase (PI3K)-specific inhibition by Wortmannin reduces Stx2-induced intracellular Ca(2+) indicating that the PI3K signaling pathway may be involved in Stx2-associated glutamate release, and that these pathways may contribute to CNS impairment associated with STEC infection.
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA ; Department of Molecular Pathology, Graduate Faculty of Interdisciplinary of Research, Graduate School, University of Yamanashi Chuo, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Obata
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Hippler
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA.
authors.forename: Progyaparamita
authors.initials: P
authors.lastname: Saha
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University Boston, MA, USA.
authors.forename: Dakshina M
authors.initials: DM
authors.lastname: Jandhyala
authors.affiliation: Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA ; Institute of Human Virology, University of Maryland School of Medicine Baltimore, MD, USA.
authors.forename: Olga S
authors.initials: OS
authors.lastname: Latinovic
keywords: Escherichia coli; PI3K; Shiga toxin; glutamates; neurons