Selective blockage of Serratia marcescens ShlA by nickel inhibits the pore forming toxin‐mediated phenotypes in eukaryotic cells

LAZZARO, M.; KRAPF, D; ELEONORA GARCIA VESCOVI

CELLULAR MICROBIOLOGY (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019

1462-5814

erratia marcescens is an opportunistic pathogen with increasing incidence in clinical settings. This is mainly attributed to the timely expression of a wide diversity of virulence factors and intrinsic and acquired resistance to antibiotics, including β‐lactams, aminoglycosides, quinolones and polypeptides. For these reasons, S. marcescens has been recently categorized by the WHO as one priority to strengthen efforts directed to develop new antibacterial agents. Therefore, it becomes critical to understand the underlying mechanisms that allow Serratia to succeed within the host. S. marcescens ShlA pore forming toxin mediates phenotypes that alter homeostatic and signal transduction pathways of host cells. It has been previously demonstrated that ShlA provokes cytotoxicity, hemolysis, autophagy and also directs Serratia egress and dissemination from invaded non‐phagocytic cells. However, molecular details of ShlA mechanism of action are still not fully elucidated. In this work, we demonstrate that Ni2+ selectively and reversibly blocks ShlA action, turning wild‐type S. marcescens into a shlA mutant strain phenocopy. Combined use of Ni2+ and calcium chelators allow to discern ShlA‐triggered phenotypes that require intracellular calcium mobilization and reveal ShlA function as a calcium channel, providing new insights into ShlA mode of action on target cells.