Detection of (oxidized) low-density lipoprotein binding ligand on Pseudomonas aeruginosa

Abstract:

[Background] Pseudomonas aeruginosa (P. aeruginosa) specifically interacts with (oxidized) low density lipoprotein (LDL/oxLDL), and RahU expressed by P. aeruginosa binds to LDL/oxLDL. [Objective] Our study investigated if RahU on P. aeruginosa was the major binding ligand for LDL/oxLDL. [Methods] The interaction of recombinant RahU (rRahU) with LDL/oxLDL was detected by ELISA. Mouse anti-rRahU antibody was generated to determine if RahU was expressed on the membrane of the wild P. aeruginosa strain by Western-Blotting and ELISA. The affinity of LDL/oxLDL bind to wild P. aeruginosa strain and ΔRahU strain (constructed as a negative control) was compared by ELISA. Influence of different protease digestion on the binding affinity of ΔRahU strain to LDL/oxLDL was also compared by ELISA. [Results] Recombinant RahU specifically interacted with LDL/oxLDL. Western-Blotting and ELISA results revealed that anti-rRahU antibody bound to the membrane protein extracted from wild P. aeruginosa strain specifically, but not with ΔRahU strain. Binding affinity of LDL/oxLDL with both wild P. aeruginosa strain and ΔRahU strain made no significant difference. Protease digestion did not influence the binding of ΔRahU strain to LDL/oxLDL. [Conclusion] RahU is one but not the unique ligand of LDL/oxLDL on P. aeruginosa.