CHEMICAL DISRUPTION OF CLPX INHIBITS MULTIRESISTANT S. AUREUS

CHEMICAL DISRUPTION OF CLPX INHIBITS MULTIRESISTANT S. AUREUS

CHALLENGE

Staphylococcus aureus is a gram-positive pathogen responsible for devasting infections of lung, skin and bones. With the onset of multiresistant S. aureus (MRSA) their treatment and prevention becomes challenging with classical antibiotics. S. aureus virulence is controlled by a complex network involving quorum sensing mediated by the accessory gene regulator (agr) system. It expresses autoinducing peptides that sense bacterial growth and initiate the production of toxins. Caseinolytic protease (ClpP) associates with chaperones such as ClpX to form a complex that recognize and unfold substrate proteins and thereby strongly influence the agr-dependent toxin expression. Several specific ClpP inhibitors have been reported foremost beta-lactones attenuating S. aureus virulence, but their facile ester bond limited pharmacological apllications. ClpX represents a crucial new target for anti-virulence strategies, however, only little is known about selective inhibitors.

INNOVATION

A high-throughput screen against the ClpXP complex was performed and identified 334 as a specific inhibitor of the ClpX chaperone that disrupts its oligomeric state. Subsequent analysis revealed strong attenuation of S. aureus toxin production, which was quantified with a customized MS-based assay platform. Transcriptome and whole-proteome studies further confirmed the global reduction of virulence and revealed characteristic signatures of protein expression in the compound-treated cells. Synthesis of 34 derivatives revealed that the molecular scaffold is restrictive for diversification, with only minor changes tolerated. Compound 367 was identified showing similar potency but reduced toxicity against A549 lung cancer cells. Furthermore, compound 367 was successfully used in a zebrafish infection model resulting in the first in vivo proof of concept.

Figure A: Structures of the two most potent hits (334 & 336) of the high-throughput screen with IC50 values. B: Supernatants of S. aureus cultures show a dose-dependent reduction of hemolysis after 20 h treatment with substance 334. C: Improvement of 334 led to compound 367 showing proof of concept in a zebrafish infection model.

COMMERCIAL OPPORTUNITIES

  • New pharmacological anti-virulence strategies
  • Available as mono therapy or as combination therapy with antibiotics
  • Applicable for following areas: bacterial virulence and leukemia

DEVELOPMENT STATUS

Proof of concept in vitro & in vivo.

Further in vivo experiments (toxicology and in mice) are currently being performed.

REFERENCES:

Fetzer, C., Korotkov, V.S., Thänert, R., Lee, K.M., Neuenschwander, M., von Kries, J.P., Medina, E., Sieber, S.A., „A Chemical Disruptor of the ClpX Chaperone Complex Attenuates the Virulence of Multidrug-Resistant Staphylococcus aureus“, Angew. Chem. Int. Edit.

Dr. Stephan Hohmann
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shohmann@baypat.de
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+49 (0) 89 5480177 - 36