TY - JOUR
T1 - The bacterial siderophore enterobactin confers survival advantage to Salmonella in macrophages
AU - Saha, Piu
AU - Xiao, Xia
AU - Yeoh, Beng San
AU - Chen, Qiuyan
AU - Katkere, Bhuvana
AU - Kirimanjeswara, Girish Soorappa
AU - Vijay-Kumar, Matam
N1 - Publisher Copyright:
© 2018, © 2018 Taylor & Francis Group, LLC.
PY - 2019/5/4
Y1 - 2019/5/4
N2 - Enterobactin (Ent), a prototypical bacterial siderophore known for its unparalleled affinity for iron, is widely conserved among members of the Enterobacteriaceae family of Gram-negative bacteria. In this study, we demonstrated that, aside from mediating iron acquisition, Ent also dampened the macrophages (MΦs) antimicrobial responses against intracellular infection by Salmonella enterica serovar Typhimurium. Accordingly, the loss of Ent expression (ΔentB) in Salmonella demoted their survivability against MΦs. Addition of exogenous Ent not only rescued the survival of ΔentB Salmonella, but also augmented WT Salmonella to better withstand the microbicidal activity of MΦs. The protection conferred to WT Salmonella was observed only when Ent was administered as iron-free, thus indicating the requirement of iron chelation in this context. In contrast, the exogenous iron-bound Ent retained its ability to promote the survival of ΔentB Salmonella, albeit modestly. Assessment on MΦs labile iron pool (LIP) revealed that iron-free Ent is able to permeate into MΦs, chelate the intracellular LIP, and regulate the expression of several key iron-regulatory proteins, i.e., divalent metal transporter 1, ferroportin, and hepcidin. Chelation of iron by Ent was also observed to promote the MΦs towards M2 polarization. Collectively, our findings demonstrated that Ent not only facilitates bacterial iron uptake but also disrupts MΦs iron homeostasis and M1/M2 polarization to safeguard intracellular bacteria against the anti-bacterial effects of their host.
AB - Enterobactin (Ent), a prototypical bacterial siderophore known for its unparalleled affinity for iron, is widely conserved among members of the Enterobacteriaceae family of Gram-negative bacteria. In this study, we demonstrated that, aside from mediating iron acquisition, Ent also dampened the macrophages (MΦs) antimicrobial responses against intracellular infection by Salmonella enterica serovar Typhimurium. Accordingly, the loss of Ent expression (ΔentB) in Salmonella demoted their survivability against MΦs. Addition of exogenous Ent not only rescued the survival of ΔentB Salmonella, but also augmented WT Salmonella to better withstand the microbicidal activity of MΦs. The protection conferred to WT Salmonella was observed only when Ent was administered as iron-free, thus indicating the requirement of iron chelation in this context. In contrast, the exogenous iron-bound Ent retained its ability to promote the survival of ΔentB Salmonella, albeit modestly. Assessment on MΦs labile iron pool (LIP) revealed that iron-free Ent is able to permeate into MΦs, chelate the intracellular LIP, and regulate the expression of several key iron-regulatory proteins, i.e., divalent metal transporter 1, ferroportin, and hepcidin. Chelation of iron by Ent was also observed to promote the MΦs towards M2 polarization. Collectively, our findings demonstrated that Ent not only facilitates bacterial iron uptake but also disrupts MΦs iron homeostasis and M1/M2 polarization to safeguard intracellular bacteria against the anti-bacterial effects of their host.
UR - http://www.scopus.com/inward/record.url?scp=85057320144&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85057320144&partnerID=8YFLogxK
U2 - 10.1080/19490976.2018.1546519
DO - 10.1080/19490976.2018.1546519
M3 - Article
C2 - 30449241
AN - SCOPUS:85057320144
SN - 1949-0976
VL - 10
SP - 412
EP - 423
JO - Gut microbes
JF - Gut microbes
IS - 3
ER -