Involvement of host cell tyrosine phosphorylation in the invasion of HEp-2 cells by Bartonella bacilliformis

Abstract

We have provided evidence that exposure of human cells to protein kinase inhibitors results in decreased invasion of these cells by Bartonella bacilliformis in a dose-dependent manner. Preincubation of human laryngeal epithelial cells in the presence of genistein, a tyrosine protein kinase inhibitor, decreased the invasion of these cells by B. bacilliformis significantly. Further, exposure of normal human umbilical vein endothelial cells to staurosporine, a potent inhibitor of protein kinase C and some tyrosine protein kinases, resulted in a considerable reduction in the number of organisms internalized by these cells. Moreover, Bartonella infection of HEp-2 cells induced tyrosine phosphorylation of several Triton X-100 soluble proteins with approximate molecular masses of 243, 215 179, 172 (doublet), 160, 145 and 110 kDa that were absent or reduced in the presence of genistein in cells after 1 h of infection. Exposure of HEp-2 cell monolayers to anti-K S and anti-L I chain integrin monoclonal antibodies resulted in a moderate decrease in the invasion of these cells, suggesting a possible role of K S L I integrins in the uptake of Bartonella into nucleated cells. z

Persistence ofBartonellaspp. stealth pathogens: from subclinical infections to vasoproliferative tumor formation

“…Early work on B. bacilliformis indicated that the bacterium is able to attach to and invade both human fibroblasts and epithelial cells (Hill et al, 1992). Moreover, it was shown that genistein, a tyrosine kinase inhibitor, decreased the invasion of the epithelial cells by B. bacilliformis (Williams-Bouyer & Hill, 1999), which indicate that the cells were actively engaged in the invasion process. Moreover, it was shown that genistein, a tyrosine kinase inhibitor, decreased the invasion of the epithelial cells by B. bacilliformis (Williams-Bouyer & Hill, 1999), which indicate that the cells were actively engaged in the invasion process.…”

“…The process appeared to require actin remodeling because cytochalasin D, a cell-permeable inhibitor of actin polymerization, inhibited the invasion (Hill et al, 1992). Interestingly, exposure of epithelial cell monolayers to anti-a5 and anti-b1 integrin monoclonal antibodies decreased the invasion of the cells by B. bacilliformis, suggesting a possible role of a5b1integrin (fibronectin receptor) in the bacterial uptake (Williams-Bouyer & Hill, 1999). Interestingly, exposure of epithelial cell monolayers to anti-a5 and anti-b1 integrin monoclonal antibodies decreased the invasion of the cells by B. bacilliformis, suggesting a possible role of a5b1integrin (fibronectin receptor) in the bacterial uptake (Williams-Bouyer & Hill, 1999).…”

Intruders below the Radar: Molecular Pathogenesis of Bartonella spp

“…The entry of B. bacilliformis was found to be fully or partially dependent on the activation of the small GTPases Rho, Rac, and Cdc42, on an altered pattern of tyrosine phosphorylation, and on ␣5␤1-integrins. Furthermore, the invasion process was dependent on a bacterial surface protein and involved actin rearrangements that manifested, during the course of intracellular persistence, as a massive formation of stress fibers anchored to focal adhesions (182,428,439). Interestingly, the intracellular vacuoles colonized by this species were shown to be associated with the Golgi complex, whose functions the pathogen could possibly manipulate in its favor, although intracellular replication has not been demonstrated (429,430).…”

Infection with Campylobacter jejuni Induces Tyrosine‐Phosphorylated Proteins into INT‐407 Cells

“…More recent studies have identified some of the specific mammalian proteins that promote uptake, and a common feature is involvement in signaling pathways regulating actin polymerization or cytoskeletal architecture (16). The induction of tyrosine phosphorylation of host cell proteins by several pathogens has been reported (4,8,31). Since protein kinases play a major role in eukaryotic cells in transducing extra cellular signals, involvement of these enzymes and protein phosphorylation in the invasion of host cells by C. jejuni is of interest.…”