Methicillin-resistant Staphylococcus aureus (MRSA) USA300 represents a clade of genetically related strains that are a major cause of skin and soft tissue infections in the hospital as well as the community settings in otherwise healthy individuals. The annual frequency of deaths from MRSA is rapidly increasing and has surpassed those caused by HIV/AIDS. Therefore, there is an urgent need to develop new treatments against MRSA. Naturally occurring antimicrobial peptides are universal host defense molecules that have retained their potency throughout the years. To effectively exploit these interesting compounds, we have been constructing, expanding, and updating the widely used Antimicrobial Peptide Database (APD; This comprehensive database facilitates naming, classification, statistical analysis, search, prediction and design of novel antimicrobials with desired properties. The APD has advanced the research and education in the antimicrobial peptide field in general and laid a solid basis for this project in particular. Based on our preliminary results, we hypothesize that most critical parameters can be extracted from the APD as a basis for designing and optimizing potent anti-MRSA peptides that cause damage on bacterial membranes, leading to bacterial death and augmenting host defense. To test our hypothesis, we have designed the following specific aims: (1) To identify the critical parameters that determine potency of anti-MRSA peptides based on the APD;(2) To elucidate the critical modulator in anti-MRSA peptides that determines mechanism of action and potential bacterial response genes;and (3) To examine the efficacy of database-designed peptides against S. aureus biofilm infection in vivo and mechanisms of immune modulation. To accomplish these aims, the PI has assembled a strong team that provides complementary expertise needed to understand host-pathogen interactions at the genetic, protein, and structural level as well as peptide-mediated immune responses in vivo using animal models. Because our database-designed compounds represent a novel anti-MRSA strategy that effectively eliminated resistant S. aureus USA300 both in vitro and in vivo, the outcome of this innovative research has great potential in providing potent anti-MRSA agents that benefit patients.

Public Health Relevance

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of great concern because of its invasive nature and capability to cause numerous life-threatening infectious diseases. The total deaths due to MRSA infection have surpassed the deaths from AIDS/HIV. Therefore, it is urgent to develop a new generation of antimicrobials. This proposal takes an innovative strategy to develop novel anti-MRSA compounds that effectively control MRSA.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
High Priority, Short Term Project Award (R56)
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Drug Discovery and Mechanisms of Antimicrobial Resistance Study Section (DDR)
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Xu, Zuoyu
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University of Nebraska Medical Center
Schools of Medicine
United States
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Wang, Guangshun; Mishra, Biswajit; Lau, Kyle et al. (2015) Antimicrobial peptides in 2014. Pharmaceuticals (Basel) 8:123-50
Tripathi, Shweta; Wang, Guangshun; White, Mitchell et al. (2015) Antiviral Activity of the Human Cathelicidin, LL-37, and Derived Peptides on Seasonal and Pandemic Influenza A Viruses. PLoS One 10:e0124706
Wang, Guangshun (2015) Improved methods for classification, prediction, and design of antimicrobial peptides. Methods Mol Biol 1268:43-66
Tripathi, Shweta; Wang, Guangshun; White, Mitchell et al. (2015) Identifying the Critical Domain of LL-37 Involved in Mediating Neutrophil Activation in the Presence of Influenza Virus: Functional and Structural Analysis. PLoS One 10:e0133454
Wang, Guangshun; Mishra, Biswajit; Epand, Raquel F et al. (2014) High-quality 3D structures shine light on antibacterial, anti-biofilm and antiviral activities of human cathelicidin LL-37 and its fragments. Biochim Biophys Acta 1838:2160-72