Aminoglycosides are broad-spectrum antibiotics used for treatment of serious bacterial infections, including the deadly tuberculosis and those accompanying AIDS, cystic fibrosis, and cancer. The emergence of pathogens resistant to these drugs represents a major threat to public health and underscores the need for new antimicrobial agents.
In Aim 1, we propose to utilize aminoglycoside-modifying enzymes of the aminoglycoside acetyltransferase (AAC) family in conjunction with a newly developed 6'-N-acylation protecting group-free chemical methodology (i) to generate in vitro libraries of new and more potent N-acylated aminoglycoside antibiotics, and (ii) to develop aminoglycoside probes that will serve as baits for identification of novel therapeutic protein targets/pathways for these antibiotics. Our chemoenzymatic and chemical strategies offer an effective solution to the following problems: (i) there are no existing general synthetic methodologies for the creation of N-acylated aminoglycosides, and (ii) there are no efficient methods to chemically modify specific amine groups on an aminoglycoside that contains a series of chemically identical amines. A few existing examples that use solely chemical syntheses are too demanding on research time and cost and are limited to very specific cases.
In Aim 2, we propose biochemical and structural studies of the mechanism of action and inhibition of a major determinant of aminoglycoside resistance in extensively drug-resistant strains of M. tuberculosis (XDR-TB). We expect this work to (i) advance the basic understanding of AG resistance of a variety of pathogenic bacteria, including M. tuberculosis, and (ii) provide a potential solution to overcome the aminoglycoside resistance problem in majority of XDR- TB. Relevance to public health: We expect that this work will contribute to the development of novel antibiotics with a potential to combat existing and newly emerging drug-resistant bacteria.

Public Health Relevance

The proposed research is relevant to public health as an improved understanding of aminoglycoside- resistance enzymes is expected to lead to the discovery and development of new drugs and also in identifying drug targets. This research will enable us to better handle the problem of resistance of infectious bacteria to aminoglycoside antibiotics. The proposed research will have a major impact in two ways: (1) our novel chemical and chemoenzymatic methodologies for the rapid and facile regio- selective N-acylation of aminoglycosides will greatly reduce the cost and effort generally associated with such modifications, and (2) our study of the mechanism of action and inhibition of the major determinant of aminoglycosdie resistance in extensively drug-resistant M. tuberculosis will advance our understanding of drug resistance and also set a new paradigm of aminoglycoside acetyltransferase in the antibiotics field.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI090048-05
Application #
8693911
Study Section
Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
Program Officer
Xu, Zuoyu
Project Start
2011-08-01
Project End
2015-07-31
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
5
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of Kentucky
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
City
Lexington
State
KY
Country
United States
Zip Code
40506
Shrestha, Sanjib K; Kril, Liliia M; Green, Keith D et al. (2017) Bis(N-amidinohydrazones) and N-(amidino)-N'-aryl-bishydrazones: New classes of antibacterial/antifungal agents. Bioorg Med Chem 25:58-66
Thamban Chandrika, Nishad; Shrestha, Sanjib K; Ngo, Huy X et al. (2017) Novel fluconazole derivatives with promising antifungal activity. Bioorg Med Chem :
Ngo, Huy X; Shrestha, Sanjib K; Green, Keith D et al. (2016) Development of ebsulfur analogues as potent antibacterials against methicillin-resistant Staphylococcus aureus. Bioorg Med Chem 24:6298-6306
Ngo, Huy X; Garneau-Tsodikova, Sylvie (2016) Flipping the Switch ""On"" for Aminoglycoside-Resistance Enzymes: The Mechanism Is Finally Revealed! Structure 24:1011-3
Chandrika, Nishad Thamban; Garneau-Tsodikova, Sylvie (2016) A review of patents (2011-2015) towards combating resistance to and toxicity of aminoglycosides. Medchemcomm 7:50-68
Willby, Melisa J; Green, Keith D; Gajadeera, Chathurada S et al. (2016) Potent Inhibitors of Acetyltransferase Eis Overcome Kanamycin Resistance in Mycobacterium tuberculosis. ACS Chem Biol 11:1639-46
Jin, Yi; Watkins, Derrick; Degtyareva, Natalya N et al. (2016) Arginine-linked neomycin B dimers: synthesis, rRNA binding, and resistance enzyme activity. Medchemcomm 7:164-169
Garneau-Tsodikova, Sylvie; Labby, Kristin J (2016) Mechanisms of Resistance to Aminoglycoside Antibiotics: Overview and Perspectives. Medchemcomm 7:11-27
Ngo, Huy X; Shrestha, Sanjib K; Garneau-Tsodikova, Sylvie (2016) Identification of Ebsulfur Analogues with Broad-Spectrum Antifungal Activity. ChemMedChem 11:1507-16
McKeating, Kristy S; Couture, Maxime; Dinel, Marie-Pier et al. (2016) High throughput LSPR and SERS analysis of aminoglycoside antibiotics. Analyst 141:5120-6

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