Mechanism of antifungal activity of antimicrobial peptide APP, a cell-penetrating peptide derivative, against Candida albicans: intracellular DNA binding and cell cycle arrest

Abstract

We investigated the antifungal properties and anti-candidal mechanism of antimicrobial peptide APP. The minimum inhibitory concentration of APP was 8 μM against Candida albicans and Aspeogillus flavus, the concentration against Saccharomyces cerevisiae and Cryptococcus neoformans was 16 μM, while 32 μM inhibited Aspergilla niger and Trichopyton rubrum. APP caused slight depolarization (12.32 ± 0.87%) of the membrane potential of intact C. albicans cells when it exerted its anti-candidal activity and only caused 21.52 ± 0.48% C. albicans cell membrane damage. APP interacted with cell wall membrane, caused potassium efflux and nucleotide leakage. However, confocal fluorescence microscopy experiment and flow cytometry confirmed that FITC-labeled APP penetrated C. albicans cell membrane with 52.31 ± 1.88% cell-penetrating efficiency and accumulated in the cytoplasm. Then, APP interact with C. albicans genomic DNA and completely suppressed DNA migration above weight ratio (peptide/DNA) of 2, and significantly arrested cell cycles during the S-phase (S-phase cell population was 27.09 ± 0.73%, p < 0.05) after penetrating the cell membrane. Results indicated that APP kills C. albicans for efficient cell-penetrating efficiency, strong DNA-binding affinity and significant physiological changes inducing S-phase arrest in intracellular environment.

Antibacterial and Antibiofilm Activity of Temporin-GHc and Temporin-GHd Against Cariogenic Bacteria, Streptococcus mutans

“…Meanwhile, the increased membrane permeability allows GHc and GHd to enter the cell and bind to DNA, contributing to a decrease in synthesis levels in bacterial DNA. These results are consistent with the findings of Li et al, who observed that the antimicrobial peptide APP damaged bacterial membrane permeability and bound to bacterial DNA to influence intracellular life activity (Li et al, 2016). According to the literature, AMPs could be used to inhibit the formation of biofilms and to eradicate mature biofilms (Mishra and Wang, 2017;Verly et al, 2017).…”

Mechanisms of Action for Antimicrobial Peptides With Antibacterial and Antibiofilm Functions

“…Membrane disruption can be further characterized by measuring which components leak out of bacterial cells, i.e., ions, ATP, or DNA/RNA. For example, cellular ions, phosphorus, and sulfur can be detected by atomic emission spectroscopy after exposing bacterial cells to HDPs (Wenzel et al, 2014(Wenzel et al, , 2015Li et al, 2016). For select ions, such as potassium, leakage can also be determined using a selective electrode (Tsutsumi et al, 2012;Wenzel et al, 2012;Hou et al, 2019).…”

Antimicrobial activity, improved cell selectivity and mode of action of short PMAP-36-derived peptides against bacteria and Candida

“…Therefore, in addition to determining antibacterial activities, we measured the in vitro antifungal properties of PMAP-36 and its derivatives against Candida in the present study. C. albicans is a common opportunistic high-infective fungus and was used as a reference fungal strain to investigate the antifungal mechanism of AMPs against Candida 192021.…”