Antagonism of a zinc metalloprotease using a unique metal-chelating scaffold: tropolones as inhibitors of P. aeruginosa elastase

Fullagar, Jessica L.; Garner, Amanda L.; Struss, Anjali K.; Day, Joshua A.; Martin, David P.; Yu, Jing; Cai, Xiaoqing; Janda, Kim D.; Cohen, Seth M.

doi:10.1039/c3cc41191e

Cited by 55 publications

(62 citation statements)

References 29 publications

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“…It also acts intracellularly in bacteria to promote biofilm formation (28) that contributes to sustained inflammation in chronic infection (13). Different inhibitors of LasB have been developed as a potential second-generation class of antibiotics that might minimize the emergence of resistant strains (25,29). Our results suggest that these inhibitors might also modulate CBG cleavage and the release of bound cortisol.…”

Section: Discussionmentioning

confidence: 70%

Pseudomonas Aeruginosa Elastase Disrupts the Cortisol-Binding Activity of Corticosteroid-Binding Globulin

et al. 2014

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The serine protease inhibitor (SERPIN) family member corticosteroid-binding globulin (CBG) is the main carrier of glucocorticoids in plasma. Human CBG mediates the targeted release of cortisol at sites of inflammation through cleavage of its reactive center loop (RCL) by neutrophil elastase. The RCLs of SERPIN family members are targeted by diverse endogenous and exogenous proteases, including several bacterial proteases. We tested different bacteria for their ability to secrete proteases that disrupt CBG cortisol-binding activity, and characterized the responsible protease and site of CBG cleavage. Serum CBG integrity was assessed by Western blotting and cortisol-binding capacity assay. Effects of time, pH, temperature, and protease inhibitors were tested. Proteolytically active proteins from bacterial media were purified by fast protein liquid chromatography, and the active protease and CBG cleavage sites were identified by mass spectrometry. Among the bacteria tested, medium from Pseudomonas aeruginosa actively disrupted the cortisol-binding activity of CBG. This proteolytic activity was inhibited by zinc chelators and occurred most efficiently at pH 7 and elevated physiological temperature (ie, 41°C). Mass spectrometric analysis of a semi-purified fraction of P. aeruginosa media identified the virulence factor LasB as the responsible protease, and this was confirmed by assaying media from LasB-deficient P. aeruginosa. This metalloprotease cleaves the CBG RCL at a major site, distinct from that targeted by neutrophil elastase. Our results suggest that humoral responses to P. aeruginosa infection are influenced by this pathogen's ability to secrete a protease that promotes the release of the anti-inflammatory steroid, cortisol, from its plasma transport protein.

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Section: Discussionmentioning

confidence: 70%

Pseudomonas Aeruginosa Elastase Disrupts the Cortisol-Binding Activity of Corticosteroid-Binding Globulin

et al. 2014

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“…This MBP library has been previously used to successfully identify scaffolds for the development of several metalloenzyme inhibitors. 35-36 …”

Section: Resultsmentioning

confidence: 99%

Discovery of an Inhibitor of the Proteasome Subunit Rpn11

Perez

Li²,

Parlati³

et al. 2017

J. Med. Chem.

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The proteasome plays a crucial role in degradation of normal proteins that happen to be constitutively or inducibly unstable, and in this capacity it plays a regulatory role. Additionally, it degrades abnormal/damaged/mutant/misfolded proteins, which serves a quality-control function. Inhibitors of the proteasome have been validated in the treatment of multiple myeloma, with several FDA-approved therapeutics. Rpn11 is a Zn2+-dependent metalloisopeptidase that hydrolyzes ubiquitin from tagged proteins that are trafficked to the proteasome for degradation. A fragment-based drug discovery (FBDD) approach was utilized to identify fragments with activity against Rpn11. Screening of a library of metal-binding pharmacophores (MBPs) revealed that 8-thioquinoline (8TQ, IC50 value ~2.5 μM) displayed strong inhibition of Rpn11. Further synthetic elaboration of 8TQ yielded a small molecule compound (35, IC50 value ~300 nM) that is a potent and selective inhibitor of Rpn11 that blocks proliferation of tumor cells in culture.

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“…P. aeruginosa elastase is a strong exotoxin that induces tissue damage; therefore, significant efforts have been made to develop chemical compounds that suppress elastase activity. Recently, the new synthetic Zn 2ϩ chelators, tropolones and N-mercaptoacetylPhe-Tyr-amide, were identified as inhibiting elastase activity in PAO1 cells (44,45). The in vivo efficacy of these two compounds, however, has not been examined.…”

Section: Discussionmentioning

confidence: 99%

A Drug-Repositioning Screening Identifies Pentetic Acid as a Potential Therapeutic Agent for Suppressing the Elastase-Mediated Virulence of Pseudomonas aeruginosa

Jeong

Lee

et al. 2014

Antimicrob Agents Chemother

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e Pseudomonas aeruginosa, a Gram-negative bacterium of clinical significance, produces elastase as a predominant exoprotease. Here, we screened a library of chemical compounds currently used for human medication and identified diethylene triamine penta-acetic acid (DTPA, pentetic acid) as an agent that suppresses the production of elastase. Elastase activity found in the prototype P. aeruginosa strain PAO1 was significantly decreased when grown with a concentration as low as 20 M DTPA. Supplementation with Zn 2؉ or Mn 2؉ ions restored the suppressive effect of DTPA, suggesting that the DTPA-mediated decrease in elastase activity is associated with ion-chelating activity. In DTPA-treated PAO1 cells, transcription of the elastase-encoding lasB gene and levels of the Pseudomonas quinolone signal (PQS), a molecule that mediates P. aeruginosa quorum sensing (QS), were significantly downregulated, reflecting the potential involvement of the PQS QS system in DTPA-mediated elastase suppression. Biofilm formation was also decreased by DTPA treatment. When A549 alveolar type II-like adenocarcinoma cells were infected with PAO1 cells in the presence of DTPA, A549 cell viability was substantially increased. Furthermore, the intranasal delivery of DTPA to PAO1-infected mice alleviated the pathogenic effects of PAO1 cells in the animals. Together, our results revealed a novel function for a known molecule that may help treat P. aeruginosa airway infection.

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Antagonism of a zinc metalloprotease using a unique metal-chelating scaffold: tropolones as inhibitors of P. aeruginosa elastase

Cited by 55 publications

References 29 publications

Pseudomonas Aeruginosa Elastase Disrupts the Cortisol-Binding Activity of Corticosteroid-Binding Globulin

Pseudomonas Aeruginosa Elastase Disrupts the Cortisol-Binding Activity of Corticosteroid-Binding Globulin

Discovery of an Inhibitor of the Proteasome Subunit Rpn11

A Drug-Repositioning Screening Identifies Pentetic Acid as a Potential Therapeutic Agent for Suppressing the Elastase-Mediated Virulence of Pseudomonas aeruginosa

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