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Cell-specific role of Hfe in Salmonella infection
bacteria when enterobactin incorporation is blocked by Lcn2. Thus, the proliferation advantage of S. Tm. in extra- cellular compartments of AlfpCre+ Hfefl/fl mice is a specific effect of increased iron availability even though it is not linked to a specific bacterial iron uptake pathway.
Hfe does not affect the phagocytic activity of macrophages
Lower bacterial numbers in Hfe-/- and LysMCre+ Hfefl/fl macrophages could theoretically be explained by altered phagocytosis. Therefore, we next compared the phago- cytic capacity of bone marrow-derived macrophages iso- lated from WT and Hfe-/- mice. However, differences were
not detected, suggesting that Hfe in macrophages does not affect the phagocytic capacity of macrophages (Online Supplementary Figure S3).
Cell type-specific Hfe deletions differentially affect iron homeostasis and anti-microbial immune gene and protein expression in spleen and liver
So far, our results indicate that lack of Hfe in macrophages is sufficient to suppress intracellular growth of S. Tm., while hepatocyte-specific Hfe depletion sup- ports iron-dependent extracellular growth of Salmonella. However, the finding that Hfe-/- and AlfpCre+ Hfefl/fl mice show comparable serum iron levels while resulting in
ABC
DEF
GHI
Figure 2. Reduced iron content in spleen and bone marrow macrophages in the absence of Hfe. Spleen sections of Hfe-/- mice (A), AlfpCre+ Hfefl/fl mice (D) and LysMCre+ Hfefl/fl mice (G) infected for 72 hours with Salmonella were stained by Prussian blue to analyze iron distribution. Scale bars: 200 mM. Iron content in infected spleen (B, E and H) and bone marrow macrophages (C, F and I) was measured and normalized for protein content. Data were compared by Mann-Whitney test. n=12 for Hfe+/+, n=12 for Hfe-/-, n=13-20 for AlfpCre– Hfefl/fl, n=11-14 for AlfpCre+ Hfefl/fl, n=10 for LysMCre– Hfefl/fl, n=10 for LysMCre+ Hfefl/fl.
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