Design, synthesis, and a novel application of quorum-sensing agonists as potential drug-delivery vehicles

Surface adhered bacterial colonies or biofilms are an important problem in medical and food industries. Bacteria use a chemical language to monitor their quorum and to express virulence factors, which eventually help them in colonization and manifestation of an infection. The LasR-LasI and RhlR-RhlI quorum-sensing (QS) systems of Pseudomonas aeruginosa control expression of virulence factors in a population density-dependent fashion. In this study we investigated the role of synthetic analogs to RhlR-RhlI system of P. aeruginosa strains (PAO-1; wild-type and mutants JP-1, PDO-100, and JP-2) responsible for production of acyl-homoserine lactones-2; butanol homoserine lactone (AHL-2; C4-HSL). We synthesized double (QS1207) and single (QS0108) sulfur analogs against (C4-HSL; AHL-2), an autoinducer of Pseudomonas QS system. Extensive biological investigation of these analogs suggested a growth promoting activity for these analogs in Pseudomonas controlling biofilm production and exo-protease secretion. We hypothesized that these thiolactone analogs could be potentially utilized as potent drug-delivery vehicles against biofilm-producing pathogens. As a proof of principle we conjugated the single sulfur analog QS0108 with the broad-spectrum antibiotic, ciprofloxacin (QS0108-Cip). The QS analog-antibiotic conjugate was significantly more effective at disrupting both the nascent and mature biofilms of P. aeruginosa than the free antibiotic.

[1]  R. Tolman,et al.  Acidic derivatives of homocysteine thiolactone: utility as anionic linkers. , 1992, Bioconjugate chemistry.

[2]  Kevin J. Dempsey,et al.  Synthesis of (S)-2-Amino-1,1-diphenylbutan-4-ol; conversion of an α-amino acid into an α-(diphenylmethyl) amine without loss of optical purity , 1995 .

[3]  Bonnie L Bassler,et al.  A quorum-sensing antagonist targets both membrane-bound and cytoplasmic receptors and controls bacterial pathogenicity. , 2009, Molecular cell.

[4]  J. Hupp,et al.  Mucin–Pseudomonas aeruginosa interactions promote biofilm formation and antibiotic resistance , 2006, Molecular microbiology.

[5]  Leo Eberl,et al.  Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound. , 2002, Microbiology.

[6]  D. Newell,et al.  Localization of immunogenic regions on the flagellin proteins of Campylobacter jejuni 81116 , 1991, Infection and immunity.

[7]  P. Seed,et al.  Activation of the Pseudomonas aeruginosa lasI gene by LasR and the Pseudomonas autoinducer PAI: an autoinduction regulatory hierarchy , 1995, Journal of bacteriology.

[8]  Roger S Smith,et al.  Roles of Pseudomonas aeruginosa las andrhl Quorum-Sensing Systems in Control of Twitching Motility , 1999, Journal of bacteriology.

[9]  B. Iglewski,et al.  Starvation Selection Restores Elastase and Rhamnolipid Production in a Pseudomonas aeruginosaQuorum-Sensing Mutant , 1998, Infection and Immunity.

[10]  J. Waitz.  Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically , 1990 .

[11]  D. Spring,et al.  Variations on a Theme: Diverse N-Acyl Homoserine Lactone-Mediated Quorum Sensing Mechanisms in Gram-Negative Bacteria , 2006, Science progress.

[12]  K. Mathee,et al.  Inhibition of Quorum Sensing-Controlled Virulence Factor Production in Pseudomonas aeruginosa by South Florida Plant Extracts , 2007, Antimicrobial Agents and Chemotherapy.

[13]  M. Kurachi.  Studies on the Biosynthesis of Pyocyanine. (II) : Isolation and Determination of Pyocyanine , 1958 .

[14]  H. Ohtake,et al.  The Synthesis of Optically Pure Enantiomers of N-Acyl-homoserine Lactone Autoinducers and Their Analogues. , 2001 .

[15]  C. Reimmann,et al.  The global activator GacA of Pseudomonas aeruginosa PAO positively controls the production of the autoinducer N‐butyryl‐homoserine lactone and the formation of the virulence factors pyocyanin, cyanide, and lipase , 1997, Molecular microbiology.

[16]  P. Stewart,et al.  Localized Gene Expression in Pseudomonas aeruginosa Biofilms , 2008, Applied and Environmental Microbiology.

[17]  E. Greenberg,et al.  Novel Pseudomonas aeruginosa Quorum-Sensing Inhibitors Identified in an Ultra-High-Throughput Screen , 2006, Antimicrobial Agents and Chemotherapy.

[18]  J. Costerton,et al.  Bacterial biofilms: a common cause of persistent infections. , 1999, Science.

[19]  H. Ohtake,et al.  Inhibition of Quorum Sensing in Pseudomonas aeruginosa by N-Acyl Cyclopentylamides , 2007, Applied and Environmental Microbiology.

[20]  Matthew R. Parsek,et al.  Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms , 2000, Nature.

[21]  I. Crawford,et al.  Identification and characterization of genes for a second anthranilate synthase in Pseudomonas aeruginosa: interchangeability of the two anthranilate synthases and evolutionary implications , 1990, Journal of bacteriology.

[22]  L. Eberl,et al.  Screening for Quorum-Sensing Inhibitors (QSI) by Use of a Novel Genetic System, the QSI Selector , 2005, Journal of bacteriology.

[23]  E. Greenberg,et al.  The potential of desferrioxamine-gallium as an anti-Pseudomonas therapeutic agent , 2008, Proceedings of the National Academy of Sciences.

[24]  E. Greenberg,et al.  A second N-acylhomoserine lactone signal produced by Pseudomonas aeruginosa. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[25]  A. Khoury,et al.  Effects of ciprofloxacin and protamine sulfate combinations against catheter-associated Pseudomonas aeruginosa biofilms , 1995, Antimicrobial agents and chemotherapy.

[26]  B. Iglewski,et al.  Quorum-Sensing Genes in Pseudomonas aeruginosa Biofilms: Their Role and Expression Patterns , 2001, Applied and Environmental Microbiology.

[27]  H. Suga,et al.  Induction and inhibition of Pseudomonas aeruginosa quorum sensing by synthetic autoinducer analogs. , 2003, Chemistry & biology.

[28]  Clinical,et al.  Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically : Approved standard , 2006 .

[29]  B. Iglewski,et al.  Azithromycin Retards Pseudomonas aeruginosa Biofilm Formation , 2004, Journal of Clinical Microbiology.