Molecular study of the Burkholderia cenocepacia division cell wall operon and FtsZ interactome as targets for new drugs

Burkholderia cenocepacia has emerged as an important opportunistic pathogen for patients suffering from cystic fibrosis. This bacterium is able to establish aggressive infections in the lungs, colonizing the viscous mucus covering the airways epithelium. Moreover, B. cenocepacia shows extremely high levels of drug resistance, making its eradication almost impossible. Bacterial divisome is considered a valuable pool of druggable targets, and this was confirmed by the characterization of C109, a potent inhibitor of the FtsZ GTPase activity, effective against B. cenocepacia and a broad-spectrum of Gram-positives and -negatives. To find more putative cellular targets, the division mechanism of B. cenocepacia was explored, starting from the characterization of the division cell wall (dcw) operon. The cluster transcriptional organization was assessed by identifying the transcription units and the transcription start site, as well as the promoter and the binding site of MraZ, the dcw transcriptional regulator. Moreover, the FtsZ interactome was dissected in B. cenocepacia, finding significant differences from the most studied microorganisms. Finally, the biofilm inhibitory potential and the cytotoxicity of the C109 nanosuspension were tested in an in vivo-like three-dimensional lung epithelial cell model. This work provides an overview of the B. cenocepacia division pathway, which will be essential for the target-based design of new drugs, and validate the antimicrobial activity of the C109 in a physiologically relevant model.