Abstract
Porcine protegrin-1 (PG-1) is a broad-spectrum antimicrobial peptide (AMP) with potent antimicrobial activities. We produced recombinant PG-1 and evaluated its cytotoxicity toward various types of mammalian cell lines, including embryonic fibroblasts, retinal cells, embryonic kidney cells, neuroblastoma cells, alveolar macrophage cells, and neutrophils. The sensitivity of the different mammalian cells to cytotoxic damage induced by PG-1 differed significantly among the cell types, with retinal neuron cells and neutrophils being the most significantly affected. A circular dichroism analysis showed there was a precise correlation between conformational changes in PG-1 and the magnitude of cytotoxicity among the various cell type. Subsequently, a green fluorescent protein (GFP) penetration assay using positively charged GFPs indicated there was a close correlation between the degree of penetration of charged GFP into cells and the magnitude of PG-1 cytotoxicity. Furthermore, we also showed that inhibition of the synthesis of anionic sulphated proteoglycans on the cell surface decreases the cytotoxic damage induced by PG-1 treatment. Taken together, the observed cytotoxicity of PG-1 towards different membrane surfaces is highly driven by the membrane’s anionic properties. Our results reveal a possible mechanism underlying cell-type dependent differences in cytotoxicity of AMPs, such as PG-1, toward mammalian cells.
Highlights
Antimicrobial peptides (AMPs) are small charged molecules that are involved in the innate immune system, and whose primary function is to eliminate invading pathogens[1,2]
Previous experiments conducted in E. coli cells have shown that the anionic nature of their membranes attracts the cationic PG-1 to their surface, and subsequently the peptide rapidly permeabilizes the membranes resulting in cell rupture[3,4]
It has been reported that the mammalian cell cytotoxicity to AMPs is generally affected by factors including the degree of hydrophobicity and the magnitude of the positive charge which influences the interactions between cell membranes and AMPs12,26,38,39
Summary
Antimicrobial peptides (AMPs) are small charged molecules that are involved in the innate immune system, and whose primary function is to eliminate invading pathogens[1,2]. They evoke activity against pathogenic bacteria by forming pores in the membrane, by inhibiting key cellular mechanisms such as translation/transcription after penetrating the cytoplasm, or by bacterial agglutination[3,4,5,6]. The more negatively charged and cholesterol-poor structure of bacterial membranes result in stronger binding of AMPs compared to their mammalian counterparts. Cytotoxicity was measured as decreases in cell viability. Five different allelic forms of PG-1 have been reported[17]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
