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Podoll JD, Rosen E, Wang W, Gao Y, Zhang J, Wang X. A small-molecule membrane fluidizer re-sensitizes methicillin-resistant Staphylococcus aureus (MRSA) to β-lactam antibiotics. Antimicrob Agents Chemother 2023; 67:e0005123. [PMID: 37681969 PMCID: PMC10583677 DOI: 10.1128/aac.00051-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 06/04/2023] [Indexed: 09/09/2023] Open
Abstract
Novel antibacterial agents and strategies are urgently needed to fight against the ongoing global antibiotic resistance problem. While natural products remain the main source in antibiotic discovery, synthetic antibacterials provide an attractive alternative and may evade the ancient antibiotic resistance. Herein, we report a small molecule that re-sensitizes methicillin-resistant Staphylococcus aureus to β-lactam antibiotics with extremely low potential for resistance development. It belongs to a new class of broad-spectrum antibacterials, trypyricins, which share similar structural characteristics and mechanism of action to the cationic antimicrobial peptides. Mechanistic studies indicated that trypyricins fluidize and disrupt bacterial cytoplasmic membrane. These results suggested that trypyricins represent a promising new class of antibacterials and may be further developed as antibiotic adjuvants to fight against resistant bacteria in the clinic.
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Affiliation(s)
| | - Emma Rosen
- Recreo Pharmaceuticals Inc, Yale Circle, Boulder, Colorado, USA
| | - Wei Wang
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
| | - Yuefeng Gao
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
| | - Jing Zhang
- Recreo Pharmaceuticals Inc, Yale Circle, Boulder, Colorado, USA
| | - Xiang Wang
- Department of Chemistry, University of Colorado, Boulder, Colorado, USA
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Katz EA, Katz SB, Fedorchuk CA, Lightstone DF, Banach CJ, Podoll JD. Increase in cerebral blood flow indicated by increased cerebral arterial area and pixel intensity on brain magnetic resonance angiogram following correction of cervical lordosis. Brain Circ 2019; 5:19-26. [PMID: 31001596 PMCID: PMC6458772 DOI: 10.4103/bc.bc_25_18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/19/2018] [Accepted: 01/16/2019] [Indexed: 11/04/2022] Open
Abstract
CONTEXT Loss of cervical lordosis is associated with decreased vertebral artery hemodynamics. AIM The aim of this study is to evaluate cerebral blood flow changes on brain magnetic resonance angiogram (MRA) in patients with loss of cervical lordosis before and following correction of cervical lordosis. SETTINGS AND DESIGN This study is a retrospective consecutive case series of patients in a private practice. MATERIALS AND METHODS Cervical lordosis of seven patients (five females and two males, 28-58 years) was measured on lateral cervical radiographs ranging from -13.1° to 19.0° (ideal is -42.0°). Brain MRAs were analyzed for pixel intensities representing blood flow. Pixel intensity of the cerebral vasculature was quantified, and percentage change was determined. STATISTICAL ANALYSIS USED A Student's t-test established significance of the percentage change in cerebral blood flow between pre- and postcervical lordosis adjustment images. Regression analysis was performed. An a priori analysis determined correlation between cervical lordosis and change in MRA pixel intensity. The statistician was blinded to the cervical lordosis. RESULTS Pixel intensity increased 23.0%-225.9%, and a Student's t-test determined that the increase was significant (P < 0.001). Regression analysis of the change in pixel intensity versus the cervical lordosis showed that as the deviation from a normal cervical lordosis increases, percentage change in pixel intensity on MRA decreases. CONCLUSION These results indicate that correction of cervical lordosis may be associated with an immediate increase in cerebral blood flow. Further studies are needed to confirm these findings and understand clinical implications.
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Affiliation(s)
| | | | | | | | | | - Jessica D Podoll
- Molecular, Cellular and Developmental Biology Department, University of Colorado Boulder, Boulder, CO, USA
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Reens AL, Crooks AL, Su CC, Nagy TA, Reens DL, Podoll JD, Edwards ME, Yu EW, Detweiler CS. A cell-based infection assay identifies efflux pump modulators that reduce bacterial intracellular load. PLoS Pathog 2018; 14:e1007115. [PMID: 29879224 PMCID: PMC6007937 DOI: 10.1371/journal.ppat.1007115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/19/2018] [Accepted: 05/21/2018] [Indexed: 12/20/2022] Open
Abstract
Bacterial efflux pumps transport small molecules from the cytoplasm or periplasm outside the cell. Efflux pump activity is typically increased in multi-drug resistant (MDR) pathogens; chemicals that inhibit efflux pumps may have potential for antibiotic development. Using an in-cell screen, we identified three efflux pump modulators (EPMs) from a drug diversity library. The screening platform uses macrophages infected with the human Gram-negative pathogen Salmonella enterica (Salmonella) to identify small molecules that prevent bacterial replication or survival within the host environment. A secondary screen for hit compounds that increase the accumulation of an efflux pump substrate, Hoechst 33342, identified three small molecules with activity comparable to the known efflux pump inhibitor PAβN (Phe-Arg β-naphthylamide). The three putative EPMs demonstrated significant antibacterial activity against Salmonella within primary and cell culture macrophages and within a human epithelial cell line. Unlike traditional antibiotics, the three compounds did not inhibit bacterial growth in standard microbiological media. The three compounds prevented energy-dependent efflux pump activity in Salmonella and bound the AcrB subunit of the AcrAB-TolC efflux system with KDs in the micromolar range. Moreover, the EPMs display antibacterial synergy with antimicrobial peptides, a class of host innate immune defense molecules present in body fluids and cells. The EPMs also had synergistic activity with antibiotics exported by AcrAB-TolC in broth and in macrophages and inhibited efflux pump activity in MDR Gram-negative ESKAPE clinical isolates. Thus, an in-cell screening approach identified EPMs that synergize with innate immunity to kill bacteria and have potential for development as adjuvants to antibiotics.
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Affiliation(s)
- Abigail L. Reens
- Department of Molecular, Cellular, & Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
| | - Amy L. Crooks
- Department of Molecular, Cellular, & Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve, Cleveland OH, United States of America
| | - Toni A. Nagy
- Department of Molecular, Cellular, & Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
| | - David L. Reens
- Department of Physics, University of Colorado Boulder, Boulder, CO, United States of America
- JILA, National Institutes of Standards and Technology and University of Colorado Boulder, Boulder, CO, United States of America
| | - Jessica D. Podoll
- Department of Molecular, Cellular, & Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
| | - Madeline E. Edwards
- Department of Molecular, Cellular, & Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
| | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve, Cleveland OH, United States of America
| | - Corrella S. Detweiler
- Department of Molecular, Cellular, & Developmental Biology, University of Colorado Boulder, Boulder, CO, United States of America
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Zhu Y, Cleaver L, Wang W, Podoll JD, Walls S, Jolly A, Wang X. Tetracyclic indolines as a novel class of β-lactam-selective resistance-modifying agent for MRSA. Eur J Med Chem 2016; 125:130-142. [PMID: 27657810 DOI: 10.1016/j.ejmech.2016.09.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/04/2016] [Accepted: 09/09/2016] [Indexed: 01/11/2023]
Abstract
Antibiotic-resistant bacterial infections have seen a marked increase in recent years, while antibiotic discovery has waned. Resistance-modifying agents (RMA) offer an intriguing alternative strategy to fight against resistant bacteria. Here we report the discovery, antibiotic profiling, and structure-activity relationships of a novel class of RMAs, tetracyclic indolines. These selectively potentiate β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) without antibacterial or β-lactamase inhibitory activity on their own. The most potent analogue, 6a, showed strong potentiation of amoxicillin/clavulanic acid in a variety of hospital-acquired and community-acquired MRSA strains with low mammalian toxicity. These compounds may be further developed to extend the clinic life span of β-lactam antibiotics.
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Affiliation(s)
- Yugen Zhu
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Lakota Cleaver
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Wei Wang
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Jessica D Podoll
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Shane Walls
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Austin Jolly
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Xiang Wang
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.
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Michael Barbour P, Podoll JD, Marholz LJ, Wang X. Discovery and initial structure-activity relationships of N-benzyl tricyclic indolines as antibacterials for methicillin-resistant Staphylococcus aureus. Bioorg Med Chem Lett 2014; 24:5602-5605. [PMID: 25466183 DOI: 10.1016/j.bmcl.2014.10.094] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 01/21/2023]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent drug resistant bacteria. In 2012, over 11,000 fatalities in the United States were directly attributable to MRSA. In an effort to develop novel structural and mechanistic classes of antibacterial agents to fight against MRSA, we have optimized a hit compound, Of4, previously discovered in a screening campaign of a bio-inspired polycyclic indoline library previously developed in our lab. We took advantage of our concise and versatile synthetic strategy to conduct initial structure-activity relationship studies of Of4, and we now report the discovery of compound 4k as a more potent antibacterial agent against S. aureus. Compound 4k also displayed equivalent activity in four MRSA and a methicillin-susceptible strains while demonstrating an improved mammalian cytotoxicity profile compared to Of4. Interestingly, 4k shares the same tricyclic indoline core as Of1, a β-lactam-selective resistance-modifying agent, but harbors a distinct modification pattern conferring unique bioactivity. This phenomenon is reminiscent of many bioactive natural products.
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Affiliation(s)
- P Michael Barbour
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, United States
| | - Jessica D Podoll
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, United States
| | - Laura J Marholz
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, United States
| | - Xiang Wang
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, United States.
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Chang L, Podoll JD, Wang W, Walls S, O'Rourke CP, Wang X. Structure-activity relationship studies of the tricyclic indoline resistance-modifying agent. J Med Chem 2014; 57:3803-17. [PMID: 24694192 PMCID: PMC4018117 DOI: 10.1021/jm500146g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
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Previously we discovered a tricyclic
indoline, N-[2-(6-bromo-4-methylidene-2,3,4,4a,9,9a-hexahydro-1H-carbazol-4a-yl)ethyl]-4-chlorobenzene-1-sulfonamide (1, Of1), from bioinspired synthesis of a highly diverse polycyclic
indoline alkaloid library, that selectively resensitizes methicillin-resistant Staphylococcus aureus strains to β-lactam antibiotics.
Herein, we report a thorough structure–activity relationship
investigation of 1, which identified regions of 1 that tolerate modifications without compromising activity
and afforded the discovery of a more potent analogue with reduced
mammalian toxicity.
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Affiliation(s)
- Le Chang
- Department of Chemistry and Biochemistry, University of Colorado Boulder , Boulder, Colorado 80309, United States
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Xu W, Podoll JD, Dong X, Tumber A, Oppermann U, Wang X. Quantitative analysis of histone demethylase probes using fluorescence polarization. J Med Chem 2013; 56:5198-202. [PMID: 23725560 DOI: 10.1021/jm3018628] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We previously reported methylstat as a selective inhibitor of jumonji C domain-containing histone demethylases (JHDMs). Herein, we describe the synthesis of a fluorescent analogue of methylstat and its application as a tracer in fluorescence polarization assays. Using this format, we have evaluated the binding affinities of several known JHDM probes, as well as the native cofactor and substrate of JHDM1A. This fluorophore allowed a highly robust and miniaturized competition assay sufficient for high-throughput screening.
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Affiliation(s)
- Wenqing Xu
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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