The continued evolution of antimicrobial resistance emphasizes the dire need for discovery of antibiotic therapeutics with novel mechanisms of action. Technological advances in genome sequencing, drug library creation, and structural informatics have not advanced infectious disease treatments sufficiently. While natural products have long served as inspiration for novel therapeutic scaffolds, we posit peptide-derived entities offer great potential to address current needs due to their unique mechanisms of action, penetration and selectively. Herein, we describe our PepSAVI-MS pipeline to discover and characterize peptides with antimicrobial activity through implementation of a hybrid bioassay-guided/peptidomics platform. We directly identify botanical peptides contributing to bioactivity profiles using robust microbial bioassays optimized for peptide screening and using a mass spectrometry-based peptidomics approach coupled to statistical modeling and informatics to identify and further characterize these peptides at the molecular level. These potential lead compounds are then tested against an extensive panel of clinical ESKAPE pathogens, as well as for favorable drug characteristics and determination of mechanism-of-action. Our platform enables robust mining of plants and other natural sources for peptidyl species with unique or broad-spectrum anti-infective properties and has the potential to lead to the discovery of novel chemistries at the forefront of modern drug discovery.

Public Health Relevance

Plant diversity has barely been tapped through either random or knowledge-based bioactivity screening approaches, and certainly not in the context of or in a manner amenable to the identification of bioactive peptides. This proposal aims to discover, characterize, and validate as potential drug lead compounds botanical antimicrobial peptides active against the ESKAPE pathogens using the PepSAVI-MS pipeline developed in our laboratory that incorporates mass spectrometry-based peptidomics and biological activity testing through statistical modeling and informatics to identify active compounds. Identifying new bioactive peptide scaffolds/lead compounds will facilitate development of treatments for drug-resistant bacterial infections in which limited or no antibiotic treatment options remain.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Synthetic and Biological Chemistry B Study Section (SBCB)
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Bond, Michelle Rueffer
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University of North Carolina Chapel Hill
Schools of Arts and Sciences
Chapel Hill
United States
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Kirkpatrick, Christine L; Parsley, Nicole C; Bartges, Tessa E et al. (2018) Exploring bioactive peptides from bacterial secretomes using PepSAVI-MS: identification and characterization of Bac-21 from Enterococcus faecalis pPD1. Microb Biotechnol 11:943-951
Parsley, Nicole C; Kirkpatrick, Christine L; Crittenden, Christopher M et al. (2018) PepSAVI-MS reveals anticancer and antifungal cycloviolacins in Viola odorata. Phytochemistry 152:61-70
Kirkpatrick, Christine L; Parsley, Nicole C; Bartges, Tessa E et al. (2018) Fungal Secretome Analysis via PepSAVI-MS: Identification of the Bioactive Peptide KP4 from Ustilago maydis. J Am Soc Mass Spectrom 29:859-865