Phellinus baumii extract influences pathogenesis of Brucella abortus in phagocyte by disrupting the phagocytic and intracellular trafficking pathway

Aims: To clarify the effects of Phellinus baumii ethanol extract (PBE) on Brucella abortus pathogenesis in phagocytes focusing on the phagocytic and intracellular trafficking pathway. Methods and Results: The effects of PBE on Br. abortus infection in macrophages were evaluated through an adherence and infection assays and an analysis of LAMP-1 staining. The phosphorylation of ERK1/2 and the F-actin polymerization associated with PBE during Br. abortus uptake were detected by immunoblotting and FACS, respectively. The survival of Br. abortus in pure culture was remarkably reduced by PBE in a dose-dependent manner. PBE-treated cells showed significantly decreased uptake, intracellular replication and adherence of Br. abortus. The declines of ERK1/2 phosphorylation and F-actin polymerization following Br. abortus entry were apparent in PBE-treated cells compared with the control. Moreover, the co-localization of Br. abortus-containing phagosomes with LAMP-1 was elevated in PBE-treated cells compared with the control during intracellular trafficking. Conclusion: Phellinus baumii ethanol extract may possess the modulatory effect on pathogenesis of Br. abortus through disrupting the phagocytic and intracellular trafficking pathway in phagocyte. Significance and Impact of the Study: The potential modulation of PBE to Br. abortus pathogenesis could provide an alternative approach to control of brucellosis, contributing to attenuate Br. abortus manifestation in hosts.