AUTHOR=Fukushima Shiho , Shimohata Takaaki , Inoue Yuri , Kido Junko , Uebanso Takashi , Mawatari Kazuaki , Takahashi Akira 

TITLE=Recruitment of LC3 by Campylobacter jejuni to Bacterial Invasion Site on Host Cells via the Rac1-Mediated Signaling Pathway

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.829682

DOI=10.3389/fcimb.2022.829682

ISSN=2235-2988

ABSTRACT=<p><italic>Campylobacter jejuni</italic> is a leading cause of food-borne disease worldwide. The pathogenicity of <italic>C. jejuni</italic> is closely associated with the internalization process in host epithelial cells, which is related to a host immune response. Autophagy indicates a key role in the innate immune system of the host to exclude invasive pathogens. Most bacteria are captured by autophagosomes and degraded by autophagosome-lysosome fusion in host cells. However, several pathogens, such as <italic>Salmonella</italic> and <italic>Shigella</italic>, avoid and/or escape autophagic degradation to establish infection. But autophagy involvement as a host immune response to <italic>C. jejuni</italic> infection has not been clarified. This study revealed autophagy association in <italic>C. jejuni</italic> infection. During infection, <italic>C. jejuni</italic> activated the Rho family small GTPase Rac1 signaling pathway, which modulates actin remodeling and promotes the internalization of this pathogen. In this study, we found the LC3 contribution to <italic>C. jejuni</italic> invasion signaling <italic>via</italic> the Rac1 signaling pathway. Interestingly, during <italic>C. jejuni</italic> invasion, LC3 was recruited to bacterial entry site depending on Rac1 GTPase activation just at the early step of the infection. <italic>C. jejuni</italic> infection induced LC3-II conversion, and autophagy induction facilitated <italic>C. jejuni</italic> internalization. Also, autophagy inhibition attenuated <italic>C. jejuni</italic> invasion step. Moreover, Rac1 recruited LC3 to the cellular membrane, activating the invasion of <italic>C. jejuni</italic>. Altogether, our findings provide insights into the new function of LC3 in bacterial invasion. We found the interaction between the Rho family small GTPase, Rac1, and autophagy-associated protein, LC3.</p>