Natural Alkaloid Berberine Activity against Pseudomonas aeruginosa MexXY-Mediated Aminoglycoside Resistance: In Silico and in Vitro Studies

Abstract

The multidrug efflux system MexXY-OprM, inside the resistance-nodulation-division (RND) family, is a major determinant of aminoglycoside resistance in Pseudomonas aeruginosa. In the fight aimed to identify potential efflux pumps inhibitors (EPIs) among natural compounds, the alkaloid berberine emerged as a putative inhibitor of MexXY-OprM. In this work, we elucidated its interaction with the extrusor protein MexY and assessed its synergistic activity with aminoglycosides. In particular, we built an in silico model for the MexY protein in its trimeric association using both AcrB (E. coli) and MexB (P. aeruginosa) as 3D templates. This model has been stabilized in the bacterial cytoplasmic membrane using a molecular dynamics approach and used for ensemble docking to obtain the binding site mapping. Then, through dynamic docking, we assessed its binding affinity and its synergism with aminoglycosides focusing on tobramycin, which is widely used in the treatment of pulmonary infections. In vitro assays validated the data obtained: the results showed a two-fold increase of the inhibitory activity and 2-4 log increase of the killing activity of the association berberine-tobramycin compared to those of tobramycin alone against 13/28 tested P. aeruginosa clinical isolates. From hemolytic assays, we preliminary assessed berberine low toxicity.

Protection of Polyphenols against Glyco-Oxidative Stress: Involvement of Glyoxalase Pathway

“…Therefore, GlxII can represent a regulatory step of the glyoxalase pathway and for this reason the activity levels of GlxII do not always have the same trend as those of GLxI. Moreover, protein–protein interaction studies, performed using a validated in silico approach [ 50 ], have been shown that GlxII could catalyze protein S-glutathionylation using S-D-lactoylglutathione as substrate, on specific redox dependent proteins [ 39 ]. This capacity implies that S-D-lactoylglutathione formation from MGO and GlxII activity could play a relevant role in the regulation of cell metabolism and redox signaling.…”

Conformational Insight on WT- and Mutated-EGFR Receptor Activation and Inhibition by Epigallocatechin-3-Gallate: Over a Rational Basis for the Design of Selective Non-Small-Cell Lung Anticancer Agents

“…The computational protocol combining Blind/focused docking in triplicate [62,63] was applied for both Erl and EGCG in association with wild type, T790M/L858R and ELREA deletion-EGFR-receptor; the most stable EGFR-ligand complexes for each couple ligand-receptro were relaxed by 20 ns of MD simulation following the MD protocol previously described. Finally, to the stability and the interaction of Erl and EGCG bound with three different EGFR forms are evaluated and compared.…”

Detection of Carbapenem-Resistance Genes in Klebsiella Species Recovered from Selected Environmental Niches in the Eastern Cape Province, South Africa

“…The resistance against antibiotics represents an important problem because the phenomenon involves different bacterial species which include Pseudomonas aeruginosa [ 5 ] and Escherichia coli [ 6 ]. Antimicrobial resistance genes (ARGs) can be transferred to other bacterial species and thereafter can lead to the production of various enzymes (such as beta-lactamases) that inactivate antimicrobial activities; the types of enzymes are myriad in carbapenemase-producing carbapenem-resistance Enterobacteriaceae (CP-CRE), and include clavulanic-acid-inhibited β-lactamases (Class A: Klebsiella pneumoniae carbapenemase, KPC; non-metallocarbapenemase, NMC; imipenemase, IMI; Serratia marcescens enzyme, SME; and Guiana extended-spectrum, GES), metallo-β-lactamases (Class B: Verona integron-encoded metallo-β-lactamase, VIM; New Delhi metallo-β-lactamase-1, NDM-1; German imipenemase, GIM; and Sao Paulo metallo-β-lactamase-1, SPM-1) and extended-spectrum oxacillinases (Class D: oxacillinase OXA-48-like) [ 7 , 8 , 9 ].…”