1
|
Ashkar SR, Rajeswaran W, Lee PH, Yeomans L, Thrasher CM, Franzblau SG, Murakami KS, Showalter HD, Garcia GA. Optimization of Benzoxazinorifamycins to Minimize hPXR Activation for the Treatment of Tuberculosis and HIV Coinfection. ACS Infect Dis 2022; 8:1408-1421. [PMID: 35772743 DOI: 10.1021/acsinfecdis.1c00635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tuberculosis (TB) is one of the most significant world health problems, responsible for 1.5 M deaths in 2020, and yet, current treatments rely largely on 40 year old paradigms. Although the rifamycins (RIFs), best exemplified by the drug rifampin (RMP), represent a well-studied and therapeutically effective chemotype that targets the bacterial RNA polymerase (RNAP), these agents still suffer from serious drawbacks including the following: 3-9 month treatment times; cytochrome P450 (Cyp450) induction [particularly problematic for human immunodeficiency virus-Mycobacterium tuberculosis (MTB) co-infection]; and the existence of RIF-resistant (RIFR) MTB strains. We have utilized a structure-based drug design approach to synthesize and test 15 benzoxazinorifamycins (bxRIFs), congeners of the clinical candidate rifalazil, to minimize human pregnane X receptor (hPXR) activation while improving potency against MTB. We have determined the compounds' activation of the hPXR [responsible for inducing Cyp450 3A4 (CYP3A4)]. Compound IC50s have been determined against the wild-type and the most prevalent RIFR (β-S450L) mutant MTB RNAPs. We have also determined their bactericidal activity against "normal" replicating MTB and a model for non-replicating, persister MTB. We have identified a minimal substitution and have probed larger substitutions that exhibit negligible hPXR activation (1.2-fold over the dimethyl sulfoxide control), many of which are 5- to 10-fold more potent against RNAPs and MTB than RMP. Importantly, we have analogues that are essentially equipotent against replicating MTB and non-replicating persister MTB, a property that is correlated with faster kill rates and may lead to shorter treatment durations. This work provides a proof of principle that the ansamycin core remains an attractive and effective scaffold for novel and dramatically improved RIFs.
Collapse
Affiliation(s)
- Shireen R Ashkar
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| | - Walajapet Rajeswaran
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States.,Vahlteich Medicinal Chemistry Core, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| | - Pil H Lee
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States.,Vahlteich Medicinal Chemistry Core, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| | - Larisa Yeomans
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| | - Claire M Thrasher
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| | - Scott G Franzblau
- Institute for Tuberculosis Research, University of Illinois, Chicago, Illinois 60612-7231, United States
| | - Katsuhiko S Murakami
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, University Park, Pennsylvania 16801, United States
| | - Hollis D Showalter
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| | - George A Garcia
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1065, United States
| |
Collapse
|
2
|
Spiropiperidyl rifabutins: expanded in vitro testing against ESKAPE pathogens and select bacterial biofilms. J Antibiot (Tokyo) 2020; 73:868-872. [PMID: 32651464 DOI: 10.1038/s41429-020-0346-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/16/2020] [Accepted: 06/20/2020] [Indexed: 11/08/2022]
Abstract
The expanded microbiological evaluation of a series of rifastures, novel spiropiperidyl rifamycin derivatives, against clinically relevant ESKAPE bacteria has identified several analogs with promising in vitro bioactivities against antibiotic-resistant strains of Enterococcus faecium and Staphylococcus aureus. Thirteen of the rifastures displayed minimum inhibitory concentrations (MICs) below 1 µg/ml against the methicillin- and vancomycin-resistant forms of S. aureus and E. faecium (MRSA, VRSA, VRE). Aryl-substituted rifastures 1, 11, and 12 offered the greatest bioactivity, with MICs reaching ≤0.063 µg ml-1 for these human pathogens. Further analysis indicates that diphenyl rifasture 1 had greater antibiofilm activity against S. aureus and lower cytotoxicity in mammalian HEK cells than rifabutin.
Collapse
|
3
|
Mosaei H, Zenkin N. Inhibition of RNA Polymerase by Rifampicin and Rifamycin-Like Molecules. EcoSal Plus 2020; 9:10.1128/ecosalplus.ESP-0017-2019. [PMID: 32342856 PMCID: PMC11168578 DOI: 10.1128/ecosalplus.esp-0017-2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Indexed: 12/16/2022]
Abstract
RNA polymerases (RNAPs) accomplish the first step of gene expression in all living organisms. However, the sequence divergence between bacterial and human RNAPs makes the bacterial RNAP a promising target for antibiotic development. The most clinically important and extensively studied class of antibiotics known to inhibit bacterial RNAP are the rifamycins. For example, rifamycins are a vital element of the current combination therapy for treatment of tuberculosis. Here, we provide an overview of the history of the discovery of rifamycins, their mechanisms of action, the mechanisms of bacterial resistance against them, and progress in their further development.
Collapse
Affiliation(s)
- Hamed Mosaei
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| | - Nikolay Zenkin
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, NE2 4AX, UK
| |
Collapse
|
4
|
Rifabutin and rifampin resistance levels and associated rpoB mutations in clinical isolates of Mycobacterium tuberculosis complex. Diagn Microbiol Infect Dis 2016; 85:177-81. [PMID: 27036978 DOI: 10.1016/j.diagmicrobio.2016.01.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/21/2016] [Accepted: 01/31/2016] [Indexed: 01/20/2023]
Abstract
Cross-resistance in rifamycins has been observed in rifampin (RIF)-resistant Mycobacterium tuberculosis complex isolates; some rpoB mutations do not confer broad in vitro rifamycin resistance. We examined 164 isolates, of which 102 were RIF-resistant, for differential resistance between RIF and rifabutin (RFB). A total of 42 unique single mutations or combinations of mutations were detected. The number of unique mutations identified exceeded that reported in any previous study. RFB and RIF MICs up to 8 μg/mL by MGIT 960 were studied; the cut-off values for susceptibility to RIF and RFB were 1 μg/mL and 0.5 μg/mL, respectively. We identified 31 isolates resistant to RIF but susceptible to RFB with the mutations D516V, D516F, 518 deletion, S522L, H526A, H526C, H526G, H526L, and two dual mutations (S522L + K527R and H526S + K527R). Clinical investigations using RFB to treat multidrug-resistant tuberculosis cases harboring those mutations are recommended.
Collapse
|
5
|
Field SK, Fisher D, Jarand JM, Cowie RL. New treatment options for multidrug-resistant tuberculosis. Ther Adv Respir Dis 2012; 6:255-68. [PMID: 22763676 DOI: 10.1177/1753465812452193] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Despite the development of effective treatments, tuberculosis (TB) remains a major health problem. TB continues to infect new victims and kills nearly 2 million people annually. The problem is much greater in resource-limited countries but is present worldwide. Inadequate public health resources, cost, the obligatory long treatment period, and adverse drug effects contribute to treatment failures and relapses. Drug-resistant Mycobacterium tuberculosis (MTB) strains arise spontaneously and are propagated by inadequate treatment. According to World Health Organization global data, 17% of MTB strains in new, previously untreated cases are resistant to at least one drug. Approximately, 3.3% of new MTB cases are resistant to both isoniazid and rifampin, also called multidrug resistant (MDR), and rates of MDR-TB are greater than 60% in previously treated patients in some countries. Approximately 5% of cases of MDR-TB are also resistant to fluoroquinolones and to injectable drugs, and are called extensively drug resistant (XDR). Recently, XDR strains have been isolated that are also resistant to all standard second-line anti-TB medications. Successful drug treatment of TB with complex resistance profiles is virtually impossible with currently available drugs. There is a desperate need for new compounds that cure strains resistant to currently available drugs and for drugs that are better tolerated and will shorten treatment regimens. In the short term, new strategies for the management of drug-resistant TB with currently available drugs are being explored. These include the use of high-dose isoniazid, substitution of rifabutin in a small proportion of rifampin-resistant cases, linezolid, fluoroquinolones, and phenothiazines. A number of novel drugs are undergoing clinical testing and will hopefully be available in the near future. These include the newer oxazolidinones, diarylquinolines, nitroimidazopyrans, ethenylenediamines, pyrroles, and benzothiazinones.
Collapse
Affiliation(s)
- Stephen K Field
- Health Science Centre, 3330 Hospital Dr. NW, Calgary, Alberta, Canada.
| | | | | | | |
Collapse
|
6
|
Gill SK, Xu H, Kirchhoff PD, Cierpicki T, Turbiak AJ, Wan B, Zhang N, Peng KW, Franzblau SG, Garcia GA, Showalter HDH. Structure-based design of novel benzoxazinorifamycins with potent binding affinity to wild-type and rifampin-resistant mutant Mycobacterium tuberculosis RNA polymerases. J Med Chem 2012; 55:3814-26. [PMID: 22452568 DOI: 10.1021/jm201716n] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
By utilization of three-dimensional structure information of rifamycins bound to RNA polymerase (RNAP) and the human pregnane X receptor (hPXR), representative examples (2b-d) of a novel subclass of benzoxazinorifamycins have been synthesized. Relative to rifalazil (2a), these analogues generally display superior affinity toward wild-type and Rif-resistant mutants of the Mycobacterium tuberculosis RNAP but lowered antitubercular activity in cell culture under both aerobic and anaerobic conditions. Lowered affinity toward hPXR for some of the analogues is also observed, suggesting a potential for reduced Cyp450 induction activity. Mouse and human microsomal studies of analogue 2b show it to have excellent metabolic stability. Mouse pharmacokinetics in plasma and lung show accumulation of 2b but with a half-life suggesting nonoptimal pharmacokinetics. These studies demonstrate proof of principle for this subclass of rifamycins and support further expansion of structure-activity relationships (SARs) toward uncovering analogues with development potential.
Collapse
Affiliation(s)
- Sumandeep K Gill
- Interdepartmental Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|