Technology Transfer Office at National Jewish Health

NJH ID: #18-03

Background
Gram-negative bacteria cause many types of infections and spread to humans in a variety of ways, producing foodborne and waterborne diseases, respiratory infections such as certain types of pneumonias, sexually transmitted diseases, or infections transmitted to people through the bite of infected insects or handling infected animals. Certain types of Gram-negative bacteria have become increasingly resistant to available antibiotics. Some strains are now resistant to all available treatments, resulting in hard to treat infections and even death, which contributes to escalating healthcare costs. Treating Gram-negative bacterial infections can be difficult because of several unique features of these bacteria. For example, the unique nature of their cell wall prevents uptake of many antibiotics. Infections have typically been treated with broad-spectrum antibiotics. However, even these drugs have become ineffective against some bacteria, leaving healthcare providers no choice but to use older drugs which can have toxic side effects. Researchers have found that RNA polymerase-binding transcription factor DksA is a transcription factor protein that acts by binding directly to RNA polymerase. DksA is required for negative regulation of rRNA expression and positive regulation of several amino acid biosynthesis promoters. In Salmonella and many other Gram-negative pathogens, DksA regulates expression of virulence programs that are essential to pathogenesis. DksA is highly conserved among Gram-negative bacteria, making this protein a potential target for small molecule antibiotics.

Technology
Scientists at the University of Colorado and National Jewish Health have identified novel compounds that specifically inhibit DksA-dependent transcription and exhibit potent anti-microbial activity. Drugs against DksA have antibiotic activity against multiple Gram-negative pathogens. Moreover, the newly discovered drugs act against persistent populations of intracellular bacteria and potentiate antimicrobial activity of other antibiotics.

Potential Applications
Infection treatment of gram-negative bacteria, including Klebsiella, E. coli, Proteus, Serratia, Salmonella, Yersinia, Enterobacter, Pseudomonas aeruginosa, Neisseria gonorrhoeae, Chlamydia trachomatis, Acinetobacter and Stenotrophomonas.

State of Development
The investigators have tested activity of the novel compounds in E.coli and Salmonella with very good results, and are currently testing the activity against several Gram-negative pathogens, including some multi-drug resistant organisms.

Publications

Vazquez-Torres A, et al. DksA–DnaJ redox interactions provide a signal for the activation of bacterial RNA polymerase, PNAS, 115(50): E11780–E11789. PMID: 30429329
Tapscott, T., J.S. Kim, M.A. Crawford, J. Westrich, L. Liu, J. Jones-Carson, and A. Vázquez-Torres. 2018. Guanosine tetraphosphate relieves the negative regulation of Salmonella pathogenicity island-2 gene transcription exerted by the AT-rich ssrA discriminator region. Scientific Reports. 8: 9465. PMID: 29930310
Crawford, M.A., T. Tapscott, L.F. Fitzsimmons, L. Liu, A.M. Reyes, S.J. Libby, M. Trujillo, F.C. Fang, R. Radi, A. Vázquez-Torres. 2016. Redox-active sensing by bacterial DksA transcription factors is determined by cysteine and zinc content. mBio. 7: e02161-15. PMID: 27094335
Henard, C.A., T. Tapscott, M.A. Crawford, M. Husain, P.T, Doulias, S. Porwollik, L. Liu, M. McClelland, H. Ischiropoulos, and A. Vázquez-Torres. 2014. The 4-Cysteine Zinc-Finger Motif of the RNA Polymerase Regulator DksA serves as a Thiol Switch for Sensing Oxidative and Nitrosative Stress. Mol. Microbiol. PMID: 24354846
Henard, C.A., & A. Vazquez-Torres. 2012. DksA-dependent resistance of Salmonella enterica Serovar Typhimurium against the Antimicrobial Activity of Inducible Nitric Oxide Synthase. Infect. Immun. 80:1373-1380. PMID: 22311927
Henard, C.A., T.J. Bourret, M. Song, & A. Vazquez-Torres. 2010. Control of redox balance by the stringent response regulatory protein promotes antioxidant defenses of Salmonella. J. Biol. Chem. 285: 36785-93. Epub 2010 Sep 17. PMID: 20851888

Patent Status
Patent application filed

Inventors
Shaodong Dai, Ph.D., Michael Wempe, Ph.D and Andrés Vázquez-Torres, DVM, Ph.D.

Licensing Status
This technology is available for licensing.

For Further Information, Contact:
Emmanuel Hilaire, PhD
Director
Technology Transfer Office
National Jewish Health
1400 Jackson Street, Room M206b
Denver, CO 80206
Voice: 303.398.1262
HilaireE@njhealth.org