Proteome analysis of outer membrane vesicles from a clinicalAcinetobacter baumanniiisolate

Abstract

The secretion of outer membrane vesicles (OMVs) is one of the major mechanisms by which Gram-negative bacteria deliver effector molecules to host cells. Acinetobacter baumannii is an important opportunistic pathogen in hospital-acquired infections, but the secretion system for effector molecules to induce host cell damage has not been characterized. In the present study, we investigated the secretion of OMVs from a clinical A. baumannii isolate and analyzed the comprehensive proteome of A. baumannii-derived OMVs. Acinetobacter baumannii secreted OMVs into the extracellular milieu during in vitro growth. Using 1-DE and LC-MS/MS protein identification and assignment analysis, 132 different proteins associated with OMVs were identified. These proteins were derived from outer membranes (n=26), periplasmic space (n=6), inner membranes (n=8), cytoplasm (n=43), and unknown localization or multiple localization sites (n=49) according to the cell location prediction programs. Among the proteins associated with OMVs, a potent cytotoxic molecule, outer membrane protein A, was highly enriched and several putative virulence-associated proteins were also identified. These results suggest that OMVs from A. baumannii are an important vehicle designed to deliver effector molecules to host cells.

Insights into Acinetobacter baumannii pathogenicity

“…Thus OmpA is one of the most well-described and important virulence factors identified in A. baumannii. It also seems that OmpA is the most abundant Omp and that it can also be secreted by A. baumannii in the form of outer membrane vesicles (37).…”

Identification of novel vaccine candidates againstAcinetobacter baumanniiusing reverse vaccinology

“…analysis of OMVs secreted by bacteria, differential expression analysis of virulent strains, in vivo animal model challenge studies, and immuno-proteomics, it provides an important platform to identify novel protective antigens. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Furthermore, through these studies and analyses, we can also deeply understand the pathogenesis of Ab bacteria. In this study, we used an integrated approach combining reverse vaccinology, bioinformatics-based structural analysis and results obtained from published proteomics studies to screen and identify potential protective antigens against Ab infections.…”

Outer Membrane Vesicle Proteomics to Discover the Pathogenicity of Acinetobacter baumannii

“…They reported a number of proteins such as β-lactamase, OmpA, chaperonin GroEL and virulenceassociated proteins in the OMVs of Acinetobacter [16]. Using OMVs proteomics, EF-Tu has been identified in the cell surface and OMVs of A. baumannii [17].…”

“…Kwon et al performed proteomics of OMVs to identify the secretion of OMVs as well as analyze the comprehensive proteome of A. baumannii-derived OMVs [16]. They reported a number of proteins such as β-lactamase, OmpA, chaperonin GroEL and virulenceassociated proteins in the OMVs of Acinetobacter [16].…”

“…Yun et al, performed differential quantitative proteomic analysis of outer membrane from multidrug-resistant Acinetobacter baumannii and reported that carbapenem induces the expression of resistance-nodulation-cell division transporters, protein kinases and suppress outer membrane proteins expression [19]. Carbapenem resistance of Acinetobacter baumannii has been studied using outer membrane proteomics between wild type and carbapenem resistance strain of Acinetobacter baumannii [12,16,21,22].…”