Figure 7.

Proposed mechanism involved in pulmonary epithelial barrier dysfunction and bacterial translocation mediated by OmpA in A. baumannii. The binding of OmpA to TLR2 activates IQGAP1/NF-κB signaling, which facilitates epithelial cytokine production (TNF-α and IL-6). Moreover, A. baumannii OmpA upregulated the binding of IQGAP1 and β-catenin, dissociated α-catenin from the β-catenin complex, and reduced E-cadherin-mediated cell–cell adhesion, it also decreased the interaction between IQGAP1 and F-actin, which led to cytoskeleton dynamic remodeling-associated inhibition of cell migration, these changes led to increased pulmonary permeability and the promotion of epithelial barrier dysfunction and A. baumannii translocation.