Di-berberine conjugates as chemical probes of Pseudomonas aeruginosa MexXY-OprM efflux function and inhibition.

• Type of Material: Article
• Authors: Logan G Kavanaugh, Emory University; Andrew R Mahoney, Emory University; Debayan Dey, Emory University; William M Wuest, Emory University; Graeme L Conn, Emory University
• Language: English
• Date: 2023-06-27
• Publisher: CSH
• Publication Version: Preprint (Prior to Peer Review)
• Copyright Statement: The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license.
• License: Creative Commons Attribution-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1101/2023.03.24.533986
• Title of Journal or Parent Work: bioRxiv
• Grant/Funding Information: This work was supported by the National Institute of General Medical Sciences (R35 GM119426 to W.M.W), National Institute of General Medical Sciences NRSA Pre-Doctoral Fellowship (F31 GM143891 to L.G.K), Cystic Fibrosis Foundation Student Traineeship (Kavana21H0 to L.G.K), an ACS MEDI Pre-doctoral Fellowship (A.R.M.), and Emory University through an Accelerator Grant from the Biological Discovery through Chemical Innovation (BDCI) initiative (to G.L.C. and W.M.W.). L.G.K.
• Keywords: Resistance-Nodulation-Division (RND); antibiotic; berberine; efflux; efflux pump inhibitor; MexXY-OprM; Pseudomonas
• Research Categories: Chemistry, Biochemistry; Chemistry, General

Abstract

The Resistance-Nodulation-Division (RND) efflux pump superfamily is pervasive among Gram-negative pathogens and contributes extensively to clinical antibiotic resistance. The opportunistic pathogen Pseudomonas aeruginosa contains 12 RND-type efflux systems, with four contributing to resistance including MexXY-OprM which is uniquely able to export aminoglycosides. At the site of initial substrate recognition, small molecule probes of the inner membrane transporter (e.g., MexY) have potential as important functional tools to understand substrate selectivity and a foundation for developing adjuvant efflux pump inhibitors (EPIs). Here, we optimized the scaffold of berberine, a known but weak MexY EPI, using an in-silico high-throughput screen to identify di-berberine conjugates with enhanced synergistic action with aminoglycosides. Further, docking and molecular dynamics simulations of di-berberine conjugates reveal unique contact residues and thus sensitivities of MexY from distinct P. aeruginosa strains. This work thereby reveals di-berberine conjugates to be useful probes of MexY transporter function and potential leads for EPI development.