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Pharmacological validation of dihydrofolate reductase as a drug target in Mycobacterium abscessus .

Authors :
Aragaw WW
Negatu DA
Bungard CJ
Dartois VA
Marrouni AE
Nickbarg EB
Olsen DB
Warrass R
Dick T
Source :
Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2024 Jan 10; Vol. 68 (1), pp. e0071723. Date of Electronic Publication: 2023 Nov 29.
Publication Year :
2024

Abstract

The Mycobacterium abscessus drug development pipeline is poorly populated, with particularly few validated target-lead couples to initiate de novo drug discovery. Trimethoprim, an inhibitor of dihydrofolate reductase (DHFR) used for the treatment of a range of bacterial infections, is not active against M. abscessus . Thus, evidence that M. abscessus DHFR is vulnerable to pharmacological intervention with a small molecule inhibitor is lacking. Here, we show that the pyrrolo-quinazoline PQD-1, previously identified as a DHFR inhibitor active against Mycobacterium tuberculosis , exerts whole cell activity against M. abscessus . Enzyme inhibition studies showed that PQD-1, in contrast to trimethoprim, is a potent inhibitor of M. abscessus DHFR and over-expression of DHFR causes resistance to PQD-1, providing biochemical and genetic evidence that DHFR is a vulnerable target and mediates PQD-1's growth inhibitory activity in M. abscessus . As observed in M. tuberculosis , PQD-1 resistant mutations mapped to the folate pathway enzyme thymidylate synthase (TYMS) ThyA. Like trimethoprim in other bacteria, PQD-1 synergizes with the dihydropteroate synthase (DHPS) inhibitor sulfamethoxazole (SMX), offering an opportunity to exploit the successful dual inhibition of the folate pathway and develop similarly potent combinations against M. abscessus . PQD-1 is active against subspecies of M. abscessus and a panel of clinical isolates, providing epidemiological validation of the target-lead couple. Leveraging a series of PQD-1 analogs, we have demonstrated a dynamic structure-activity relationship (SAR). Collectively, the results identify M. abscessus DHFR as an attractive target and PQD-1 as a chemical starting point for the discovery of novel drugs and drug combinations that target the folate pathway in M. abscessus .<br />Competing Interests: C.J.B., A.E.M., E.B.N., D.B.O., and R.W. are employees of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Details

Language :
English
ISSN :
1098-6596
Volume :
68
Issue :
1
Database :
MEDLINE
Journal :
Antimicrobial agents and chemotherapy
Publication Type :
Academic Journal
Accession number :
38018963
Full Text :
https://doi.org/10.1128/aac.00717-23