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Singleton AH, Bergum OET, Søgaard CK, Røst LM, Olsen CE, Blindheim FH, Ræder SB, Bjørnstad FA, Sundby E, Hoff BH, Bruheim P, Otterlei M. Activation of multiple stress responses in Staphylococcus aureus substantially lowers the minimal inhibitory concentration when combining two novel antibiotic drug candidates. Front Microbiol 2023; 14:1260120. [PMID: 37822747 PMCID: PMC10564113 DOI: 10.3389/fmicb.2023.1260120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/05/2023] [Indexed: 10/13/2023] Open
Abstract
The past few decades have been plagued by an increasing number of infections caused by antibiotic resistant bacteria. To mitigate the rise in untreatable infections, we need new antibiotics with novel targets and drug combinations that reduce resistance development. The novel β-clamp targeting antimicrobial peptide BTP-001 was recently shown to have a strong additive effect in combination with the halogenated pyrrolopyrimidine JK-274. In this study, the molecular basis for this effect was examined by a comprehensive proteomic and metabolomic study of the individual and combined effects on Staphylococcus aureus. We found that JK-274 reduced activation of several TCA cycle enzymes, likely via increasing the cellular nitric oxide stress, and BTP-001 induced oxidative stress in addition to inhibiting replication, translation, and DNA repair processes. Analysis indicated that several proteins linked to stress were only activated in the combination and not in the single treatments. These results suggest that the strong additive effect is due to the activation of multiple stress responses that can only be triggered by the combined effect of the individual mechanisms. Importantly, the combination dose required to eradicate S. aureus was well tolerated and did not affect cell viability of immortalized human keratinocyte cells, suggesting a species-specific response. Our findings demonstrate the potential of JK-274 and BTP-001 as antibiotic drug candidates and warrant further studies.
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Affiliation(s)
- Amanda Holstad Singleton
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | | | - Caroline Krogh Søgaard
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Lisa Marie Røst
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Cecilie Elisabeth Olsen
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Fredrik Heen Blindheim
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Synnøve Brandt Ræder
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Frithjof A. Bjørnstad
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Eirik Sundby
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Bård Helge Hoff
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Per Bruheim
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Marit Otterlei
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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Halogenated Pyrrolopyrimidines with Low MIC on Staphylococcus aureus and Synergistic Effects with an Antimicrobial Peptide. Antibiotics (Basel) 2022; 11:antibiotics11080984. [PMID: 35892374 PMCID: PMC9330635 DOI: 10.3390/antibiotics11080984] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/16/2022] Open
Abstract
Currently, there is a world-wide rise in antibiotic resistance causing burdens to individuals and public healthcare systems. At the same time drug development is lagging behind. Therefore, finding new ways of treating bacterial infections either by identifying new agents or combinations of drugs is of utmost importance. Additionally, if combination therapy is based on agents with different modes of action, resistance is less likely to develop. The synthesis of 21 fused pyrimidines and a structure-activity relationship study identified two 6-aryl-7H-pyrrolo [2,3-d] pyrimidin-4-amines with potent activity towards Staphylococcus aureus. The MIC-value was found to be highly dependent on a bromo or iodo substitution in the 4-benzylamine group and a hydroxyl in the meta or para position of the 6-aryl unit. The most active bromo and iodo derivatives had MIC of 8 mg/L. Interestingly, the most potent compounds experienced a four-fold lower MIC-value when they were combined with the antimicrobial peptide betatide giving MIC of 1–2 mg/L. The front runner bromo derivative also has a low activity towards 50 human kinases, including thymidylate monophosphate kinase, a putative antibacterial target.
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