Enhancement of neutrophil chemotaxis by trans-anethole-treated Staphylococcus aureus strains

Abstract

This study aimed to analyze the chemotactic response of differentiated HL-60 neutrophil-like (dHL-60) cells totrans-anethole (TA)-treatedStaphylococcus aureusstrains. Special attention was paid to evaluate the influence of TA on thechpgene expression level, as well as molecular docking and molecular dynamics (MD) simulation studies on interactions of TA with chemotaxis inhibitory protein ofS.aureus(CHIPS). The following parameters were studied: susceptibility to TA using the agar diffusion method, thechpgene detection and its expression under TA influence, and clonal diversity ofS.aureusstrains using molecular techniques. Furthermore, a chemotactic response of dHL-60 cells to TA-treatedS.aureususing Boyden chamber assay was detected and molecular modeling using both the docking methodology and unbiased MD simulations was conducted. It was found that TA showed antibacterial activity against all strains. Three genotypes and one unique pattern were distinguished among the strains. 50% of the isolates werechp-positive. It was observed that TA reduced/inhibitedchpgene expression in mostS.aureusstrains. Enhanced chemotactic response of dHL-60 cells to TA-treatedS.aureusstrains was also noted. This correlation was similar for bothchp-positive andchp-negative strains. Both molecular docking and MD simulations studies confirmed that TA is preferentially bound in the complement component 5a/CHIPS interface interaction region and can interfere with any processes exploiting this binding cavity. It has been proven that dHL-60 cells exhibited a higher chemotactic response to TA-treatedS.aureusstrains in comparison to non-treated bacteria, regardless of the achieved expression of thechpgene or its lack. Nevertheless, further analyses are required to understand this mechanism better.