Antimicrobial peptides are a
distinctive1 class of
potent2, broad-spectrum
antibiotics4 produced by the body's
innate5 immune system -- the first line of
defense6 against disease-causing microbes. In a new study, Yixin Shi, Ph.D., and Wei Kong, Ph.D., researchers in the Center for Infectious Diseases and Vaccinology at Arizona State University's Biodesign Institute, explore the clever techniques used by bacteria to survive destruction from antimicrobial peptides -- potent defense factors produced by all living forms, including humans.
Professor Shi underscores the importance of antimicrobial peptides in the pitched battle against multi-drug
resistant7 bacteria:
"All bacteria treated with conventional antibiotics will develop
antibiotic3 resistance," he says. "But antimicrobial peptides have a unique function. Many of them target the
bacterial8 membrane9, making it very difficult for bacteria to develop resistance." After fusing with the invasive bacteria's membrane, antimicrobial peptides cause membrane
leakage10, leading to cell destruction or lysis.
The researchers describe one strategy bacteria have evolved to try to shield themselves from the effects of antimicrobial peptides, allowing the pathogens to survive efforts to
eradicate11 them. A two-component system, used by pathogenic
invaders12 like E coli and Salmonella, facilitates expression of multi-drug pumps that can remove antimicrobial peptides from the bacterium's cytoplasm.
The study's findings suggest that if this two-component system could be disabled, disease-causing bacteria would fall victim to the
lethal13 effects of antimicrobial peptides. The research helps open the door to the clinical application of these powerful antibiotics at a time when such novel therapeutics are
desperately14 needed to stem the tide of bacterial resistance.
Scientific collaborators from ASU's School of Life Sciences as well as researchers from the College of Life Sciences, Inner Mongolia University, China and the State Key Laboratory of
Pharmaceutical15 Biotechnology, Nanjing University, China join Drs. Shi and Kong.
The group's research results recently appeared in the Journal of Biological Chemistry.
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