Internalization of Aeromonas hydrophila by fish epithelial cells can be inhibited with a tyrosine kinase inhibitor

Abstract

Aeromonas hydrophila is a Gram-negative bacterium that is pathogenic in fish, causing motile aeromonad septicaemia. It can enter (invade) fish cells, and survive as an intracellular parasite. The host-pathogen interaction and signal transduction pathway were studied by screening signal transduction inhibitors using carp epithelial cells and a virulent strain of the bacterium, PPDl34/91. Genistein, a tyrosine kinase inhibitor, postponed internalization of A. hydrophila into host cells, suggesting that tyrosine phosphorylation plays a role in internalization. In contrast, staurosporine, a protein kinase C inhibitor, and sodium orthovanadate, a protein tyrosine phosphatase inhibitor, accelerated internalization of PPD134/91. Other virulent strains of A. hydrophila were also examined and it is likely that all strains, irrespective of serogroup, use the same signalling pathway to facilitate bacterial uptake.

Changes in adhesion ability of Aeromonas hydrophila during long exposure to salt stress conditions

“…Furthermore, in some cases, TEM revealed bacteria within the vacuoles, thus demonstrating both the ability to adhere to and invade epithelial cells. This is in agreement with other authors who report the ability of Aeromonas members to internalize (Lawson et al 1985;Granum et al 1998;Tan et al 1998).…”

A Type III Secretion System Is Required for Aeromonas hydrophila AH-1 Pathogenesis

“…EPC cells were infected with AH-1 and the aopB and aopD mutants. Upon infection with A. hydrophila AH-1, the EPC cells underwent a series of cytopathic changes similar to those of another strain, PPD134/91, as described in an earlier study (40). The cells infected with AH-1 progressively detached from one another, elongated to form long spindles, became rounded, and eventually detached from one another and also from the well.…”

“…Cells were grown in 75-cm 2 flasks and split at least once a week by trypsin-EDTA treatment and dilution at 1:10 in fresh medium. Studies on morphological changes were conducted by seeding 5 ϫ 10 5 fish cells into each well of a 24-well tissue culture plate (Falcon) and then proceeding as described previously (40). EPC monolayers were infected with A. hydrophila cells suspended in phosphate-buffered saline (PBS) (137 mM NaCl, 2.7 mM KCl, 4.3 mM Na 2 HPO 4 , 1.4 mM KH 2 PO 4 [pH 7.2]) at a multiplicity of infection (MOI) (number of bacteria per cultured cell) of 1.…”

Role of Microfilaments and Microtubules in the Invasion of EPC Cells by Aeromonas hydrophila

“…Bacterial internalization has typically been observed to involve rearrangement of the host cytoskeletal structure, resulting in endocytosis of the pathogen. Signal transduction participates in the internalization of A. hydrophila (Tan et al., 1998; Chu and Lu, 2003). Low et al.…”