A high-throughput small-molecule screen to identify a novel chemical inhibitor of Clostridium difficile

Katzianer, David S.; Yano, Takahiro; Rubin, Harvey; Zhu, Jun

doi:10.1016/j.ijantimicag.2014.03.007

Cited by 5 publications

(5 citation statements)

References 15 publications

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“…1,10-Phenanthroline has been shown to mediate microbial killing by virtue of its ability to either bind DNA, chelate metal ions, or inhibit acetyl coenzyme A synthesis (30,(39)(40)(41). However, in this study, we demonstrate that the chelation of metal ions is not the mechanism by which 5NP inhibits M. tuberculosis growth in vitro.…”

Section: Discussioncontrasting

confidence: 55%

“…The compounds in the 1,10-phenanthroline series act as powerful chelating agents by virtue of their ability to form thermodynamically stable metal ion complexes. These phenanthroline-metal complexes have been demonstrated to inhibit the growth of drug-resistant Pseudomonas aeruginosa and Clostridium difficile strains (30,31) and also inhibit biofilm formation by P. aeruginosa and Enterococcus faecalis (31,32). The 1,10-phenanthroline compounds also possess fungistatic activity by inhibiting the secretory metallopeptidase of Phialophora verrucosa (33).…”

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confidence: 99%

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Dual Mechanism of Action of 5-Nitro-1,10-Phenanthroline against Mycobacterium tuberculosis

Kidwai

Park

Mawatwal

et al. 2017

Antimicrob Agents Chemother

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New chemotherapeutic agents with novel mechanisms of action are urgently required to combat the challenge imposed by the emergence of drug-resistant mycobacteria. In this study, a phenotypic whole-cell screen identified 5-nitro-1,10-phenanthroline (5NP) as a lead compound. 5NP-resistant isolates harbored mutations that were mapped to and were also resistant to the bicyclic nitroimidazole PA-824. Mechanistic studies confirmed that 5NP is activated in an F-dependent manner, resulting in the formation of 1,10-phenanthroline and 1,10-phenanthrolin-5-amine as major metabolites in bacteria. Interestingly, 5NP also killed naturally resistant intracellular bacteria by inducing autophagy in macrophages. Structure-activity relationship studies revealed the essentiality of the nitro group for activity, and an analog, 3-methyl-6-nitro-1,10-phenanthroline, that had improved activity and efficacy in mice compared with that of 5NP was designed. These findings demonstrate that, in addition to a direct mechanism of action against, 5NP also modulates the host machinery to kill intracellular pathogens.

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Section: Discussioncontrasting

confidence: 55%

mentioning

confidence: 99%

Dual Mechanism of Action of 5-Nitro-1,10-Phenanthroline against Mycobacterium tuberculosis

Kidwai

Park

Mawatwal

et al. 2017

Antimicrob Agents Chemother

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“…Cernat and Scott failed after DPP treatment of C. difficile to recover the bacterial growth by the addition of alternative iron sources including lactoferrin, transferrin, hemoprotein, and heme (Cernat and Scott, 2012). A high-throughput small molecule screen identified DPP as one of the most potent inhibitors of C. difficile growth, even in a mouse model (Katzianer et al, 2014). Latter indicated the importance of iron for C. difficile growth, but also showed the detrimental effects of DPP treatment.…”

Section: Resultsmentioning

confidence: 99%

Iron Regulation in Clostridioides difficile

et al. 2018

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The response to iron limitation of several bacteria is regulated by the ferric uptake regulator (Fur). The Fur-regulated transcriptional, translational and metabolic networks of the Gram-positive, pathogen Clostridioides difficile were investigated by a combined RNA sequencing, proteomic, metabolomic and electron microscopy approach. At high iron conditions (15 μM) the C. difficile fur mutant displayed a growth deficiency compared to wild type C. difficile cells. Several iron and siderophore transporter genes were induced by Fur during low iron (0.2 μM) conditions. The major adaptation to low iron conditions was observed for the central energy metabolism. Most ferredoxin-dependent amino acid fermentations were significantly down regulated (had, etf, acd, grd, trx, bdc, hbd). The substrates of these pathways phenylalanine, leucine, glycine and some intermediates (phenylpyruvate, 2-oxo-isocaproate, 3-hydroxy-butyryl-CoA, crotonyl-CoA) accumulated, while end products like isocaproate and butyrate were found reduced. Flavodoxin (fldX) formation and riboflavin biosynthesis (rib) were enhanced, most likely to replace the missing ferredoxins. Proline reductase (prd), the corresponding ion pumping RNF complex (rnf) and the reaction product 5-aminovalerate were significantly enhanced. An ATP forming ATPase (atpCDGAHFEB) of the F0F1-type was induced while the formation of a ATP-consuming, proton-pumping V-type ATPase (atpDBAFCEKI) was decreased. The [Fe-S] enzyme-dependent pyruvate formate lyase (pfl), formate dehydrogenase (fdh) and hydrogenase (hyd) branch of glucose utilization and glycogen biosynthesis (glg) were significantly reduced, leading to an accumulation of glucose and pyruvate. The formation of [Fe-S] enzyme carbon monoxide dehydrogenase (coo) was inhibited. The fur mutant showed an increased sensitivity to vancomycin and polymyxin B. An intensive remodeling of the cell wall was observed, Polyamine biosynthesis (spe) was induced leading to an accumulation of spermine, spermidine, and putrescine. The fur mutant lost most of its flagella and motility. Finally, the CRISPR/Cas and a prophage encoding operon were downregulated. Fur binding sites were found upstream of around 20 of the regulated genes. Overall, adaptation to low iron conditions in C. difficile focused on an increase of iron import, a significant replacement of iron requiring metabolic pathways and the restructuring of the cell surface for protection during the complex adaptation phase and was only partly directly regulated by Fur.

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“…C. difficile strains CD630, UK1 (from J. Sorg, Texas A&M University), and VPI10463 (ATCC 43255) were grown as described previously [13] in an anaerobic workstation (Coy Laboratory Productions, USA) at 37°C in pre-reduced BHIS, Brain-Heart Infusion (Bacto, USA) medium supplemented with yeast extract (5 mg/mL; Bacto, USA) and L-cysteine (0.1% wt/vol; Sigma-Aldrich, St. Louis, MO). An anaerobic atmosphere was maintained with 5% H 2 , 5% CO 2 , and 90% N 2 .…”

Section: Methodsmentioning

confidence: 99%

Clostridium difficile contains plasmalogen species of phospholipids and glycolipids

Guan

Katzianer

Zhu

et al. 2014

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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Analysis of the polar lipids of many pathogenic and non-pathogenic clostridia has revealed the presence of plasmalogens, alk-1′-enyl ether-containing phospholipids and glycolipids. An exception to this finding so far has been Clostridium difficile, an important human pathogen which is the cause of antibiotic-associated diarrhea and other more serious complications. We have examined the polar lipids of three strains of C. difficile by thin-layer chromatography and have found acid-labile polar lipids indicative of the presence of plasmalogens. The lipids from one of these strains were subjected to further analysis by liquid chromatography coupled to electrospray ionization-mass spectrometry (LC/ESI-MS), which revealed the presence of phosphatidylglycerol, cardiolipin, monohexosyldiradylglycerol, dihexosyldiradylglycerol, and two unusual glycolipids identified as an aminohexosyl-hexosyldiradylglycerol, and a trihexosyldiradylglycerol. High resolution tandem mass spectrometry determined that monohexosyldiradylglycerol, cardiolipin and phosphatidylglycerol contained significant amounts of plasmalogens. C. difficile thus joins the growing list of clostridia that have plasmalogens. Since plasmalogens in clostridia are formed by an anaerobic pathway distinct from that in animal cells, their formation represents a potential novel target for antibiotic action.

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A high-throughput small-molecule screen to identify a novel chemical inhibitor of Clostridium difficile

Cited by 5 publications

References 15 publications

Dual Mechanism of Action of 5-Nitro-1,10-Phenanthroline against Mycobacterium tuberculosis

Dual Mechanism of Action of 5-Nitro-1,10-Phenanthroline against Mycobacterium tuberculosis

Iron Regulation in Clostridioides difficile

Clostridium difficile contains plasmalogen species of phospholipids and glycolipids

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