Exploring calcium channel blocker as a candidate drug for Pseudomonas aeruginosa through network pharmacology and experimental validation.

Calcium channel blocker (CCB) is known to possess antibacterial effects. We aimed to apply network pharmacology (docking and protein-protein interaction [PPI] analyses) to predict the potential targets and mechanisms of CCB against Pseudomonas aeruginosa (PA) as well as to verify the effect of these drugs. The chemical structures of three CCBs were obtained through the Drug Bank platform. The potential channel proteins, efflux pump proteins and ion channel proteins of CCB against bacteria were derived from the literature. These proteins were collected through the PDB and Uniprot platform. The binding mode of the docking complexes was simulated by the CB-Dock platform and Discovery Studio 2019 Client software. The PPI network was constructed by the String platform and Cytoscape 3.8.2 platform. GO was explained by the PANTHER platform. The pathway diagram was drawn with the Pathway Builder Tool 2.0 software. The inhibitory effect of CCB on PA was verified through antibacterial experiments. Finally, 76 proteins were obtained: the iron channel protein of PA demonstrated a good docking relationship with all three CCBs, and the optimum binding energy was approximately -9.0 kcal/mol. GO analysis (biological process [BP], cellular component [CC], and molecular function [MF]) of protein genes showed a good docking relationship (optimum binding energy <-8.0 kcal/mol). The MF annotation results indicated that the target of CCB may be present on the PA membrane protein. The ion channel protein PPI enrichment p-value was 6.65e-08, and PfeA showed the strongest correlation. The experimental results suggested that CCB could inhibit the growth of PA. CCB might be an effective and interesting antimicrobial treatment strategy as CCB can potentially inhibit the growth of PA.