Membrane Transporters Involved in the Antimicrobial Activities of Pyrithione in Escherichia coli

Abstract

Pyrithione (2-mercaptopyridine-N-oxide) is a metal binding modified pyridine, the antibacterial activity of which was described over 60 years ago. The formulation of zinc-pyrithione is commonly used in the topical treatment of certain dermatological conditions. However, the characterisation of the cellular uptake of pyrithione has not been elucidated, although an unsubstantiated assumption has persisted that pyrithione and/or its metal complexes undergo a passive diffusion through cell membranes. Here, we have profiled specific membrane transporters from an unbiased interrogation of 532 E. coli strains of knockouts of genes encoding membrane proteins from the Keio collection. Two membrane transporters, FepC and MetQ, seemed involved in the uptake of pyrithione and its cognate metal complexes with copper, iron, and zinc. Additionally, the phenotypes displayed by CopA and ZntA knockouts suggested that these two metal effluxers drive the extrusion from the bacterial cell of potentially toxic levels of copper, and perhaps zinc, which hyperaccumulate as a function of pyrithione. The involvement of these distinct membrane transporters contributes to the understanding of the mechanisms of action of pyrithione specifically and highlights, more generally, the important role that membrane transporters play in facilitating the uptake of drugs, including metal–drug compounds.

Metal Complexes of Omadine (N-Hydroxypyridine-2-thione): Differences of Antioxidant and Pro-Oxidant Behavior in Light and Dark Conditions with Possible Toxicity Implications

“…Omadine was proposed as a potential drug capable of initiating and accelerating the process of oxidative stress toxicity, including ferroptotic cell death. Several properties of OM fulfill this role, including the binding of metal ions, such as iron, copper, and zinc; membranotropic activity; and also the pro-oxidant activity in photochemical reactions with the formation of hydroxyl radicals [ 29 , 72 , 73 , 74 , 75 ]. There are many studies reported regarding the possible use of OM and its metal complexes as potential anticancer drugs [ 2 , 30 , 31 , 32 , 33 , 44 , 45 , 73 , 75 ].…”

Analysis of a Library of Escherichia coli Transporter Knockout Strains to Identify Transport Pathways of Antibiotics

“…Gene knockouts are well-known to cause pleiotropic effects, with knockouts of a single gene often causing altered expression in many other genes that may affect transporter sensitivity [ 33 ]. Further validation of predicted effects can be achieved by use of the ‘ASKA’ overexpression collection [ 34 ], where, if the opposite effect is observed (e.g., resistance in an overexpression strain and sensitivity in a knockout strain), this could be seen as providing further evidence that the compound is indeed a substrate of the given transporter [ 19 , 35 , 36 ]. Given the large degree of redundancy in transporters (i.e., a given substrates may be transported by several transporters), more robust follow-up results could be achieved through investigation of double knockouts, as has recently been demonstrated in yeast [ 37 ].…”

Intelligent host engineering for metabolic flux optimisation in biotechnology

“…In addition, it is (somewhat astonishingly [501]) widely still believed (or at least assumed) that all kinds of substrates simply cross biological membrane via passage through any bilayer that may be present. The facts are otherwise [176,[502][503][504][505][506][507][508][509]. Those references rehearse the fact that even tiny molecules like water [510,511] do not pass unhindered through phospholipid bilayers in real biological membranes (whose protein : lipid ratio by mass is often 3 : 1), but require transporters.…”