Specific adherence of Borrelia burgdorferi extracellular vesicles to human endothelial cells in culture

Abstract

Borrelia burgdorferi produces extracellular vesicles which contain some of the outer surface proteins of the bacterium (e.g., OspA and OspB). Borrelial vesicles, isolated by differential centrifugation and filtration, were tested for the ability to bind to cultured human umbilical vein endothelial (HUVE) cells in culture. The recently described lipoprotein OspD was expressed on vesicles. Vesicles exhibited differential expression of OspB and OspD in a relationship with passage number and medium serum supplement type, respectively. Qualitative immunoblotting analyses demonstrated dose-dependent, passage number-dependent adsorption of vesicles by HUVE cells. This adsorption was demonstrated to be dependent upon a borrelial component of the vesicle and not due to the presence of minor contamination with intact spirochetes. Quantitative experiments examining inhibition of B. burgdorferi-HUVE association as a function of prior vesicle-HUVE association demonstrated dependence upon (i) a borrelial component(s) in the vesicle, (ii) low passage number, and (iii) vesicle protein concentration. However, vesicle pretreatment of the HUVE cell monolayer was not requisite for this inhibition.Vesicles from highly passaged borrelias were noninhibitory for B. burgdorferi-HUVE cell association, regardless of the serum used to supplement the medium. The use of vesicles as a tool for studying B. burgdorjeri pathogenesis and/or physiology is proposed.

Enterotoxigenic Escherichia coli vesicles target toxin delivery into mammalian cells

“…OmpA is a major vesicle component for all strains of E. coli we have investigated thus far (Horstman and Kuehn, 2000; our unpublished data), and OmpA has a receptor on human brain endothelial cells and also triggers lipid raft‐dependent internalization (Prasadarao, 2002). It is unclear whether toxin mediates the eukaryotic cell interactions of vesicles from Shigella flexneri , Borrelia burgdorferi , and P. aeruginosa , and cytotoxin‐containing E. coli vesicles interact with eukaryotic cells (Shoberg and Thomas, 1993; Kadurugamuwa and Beveridge, 1998; Beermann et al , 2000; Wai et al , 2003). Nontoxin‐mediated vesicle adhesion and endocytosis may play an equally important role in pathogenesis since these bacterial vesicles could deliver active lumenal toxins and endotoxins into the eukaryotic cell.…”

The outer membrane vesicles: Secretion system type zero

“…Nevertheless, in asymptomatic carriers and symptomatic patients infected with N meningitidis, OMVs in blood and in spinal fluid were detected. Similarly, the presence of OMVs in Borrelia burgdorferi has been demonstrated in urine samples and mouse blood, as well as in infected ticks; so, the presence of OMVs in bodily fluids of infected hosts demonstrates their ability to migrate and act away from the site of infection; this is of great importance in the establishment of chronic infections 57‐59 …”

Multicomponent Moraxella catarrhalis outer membrane vesicles induce an inflammatory response and are internalized by human epithelial cells

“…Several studies have demonstrated that OMVs play a role as protective transport vesicles, delivering toxins, enzymes and DNA to eukaryotic cells as well as being key factors in natural competence (Deich and Hoyer, 1982; Dorward et al ., 1989; Kadurugamuwa and Beveridge, 1998; Kesty et al ., 2004; Renelli et al ., 2004). OMVs can also improve bacterial survival in the host by directly mediating bacterial binding and invasion, causing cytotoxicity and modulating the host immune response (Shoberg and Thomas, 1993; Bomberger et al ., 2009). We have previously shown that OMVs from M. catarrhalis contribute to an increased survival of Haemophilus influenzae in human serum by binding and neutralizing C3 in vitro (Tan et al ., 2007).…”