Exposure of Escherichia coli to human hepcidin results in differential expression of genes associated with iron homeostasis and oxidative stress

Hepcidin belongs to the antimicrobial peptide family but has weak activity with regards to bacterial killing. The regulatory function of hepcidin in humans serves to maintain an iron-restricted environment that limits the growth of pathogens; this study explored whether hepcidin affected bacterial iron homeostasis and oxidative stress using the model organism Escherichia coli. Using the Miller assay it was determined that under low iron availability exposure to sub-inhibitory doses of hepcidin (4-12μM) led to 2-fold and 4-fold increases in the expression of ftnA and bfd, respectively (P < 0.05), in both a wild type (WT) and Δfur (ferric uptake regulator) background. Quantitative real-time PCR analysis of oxyR and sodA, treated with 4 or 8 μM of hepcidin showed that expression of these genes was significantly (P < 0.05) increased, whereas expression of lexA was unchanged, indicating that hepcidin likely mediated oxidative stress but did not induce DNA damage.