Mycobacteria-induced anaemia: a molecular approach reveals the involvement of NRAMP1 and lipocalin-2 but not hepcidin

Anaemia is a frequent complication of chronic infectious diseases but the exact mechanisms by which it develops remain to be clarified. In the present work, we used a mouse model of mycobacterial infection to study molecular alterations of iron metabolism. We show that four weeks after infection with Mycobacterium avium BALB/c mice exhibit a moderate anaemia, which cannot be explained by elevated hepatic hepcidin mRNA expression. Instead, the mice respond with increased mRNA expression of ferroportin (Slc40a1), ceruloplasmin (Cp), hemopexin (Hpx), heme-oxygenase-1 (Hmox1) and lipocalin-2 (Lcn2). Both the anemia and the mRNA expression changes of iron-related genes are largely absent in C.D2 mice which bear a functional allele of the Nramp1 gene. These data suggest that anaemia due to a chronic infection with M. avium develops independently of elevated hepcidin expression and possibly involves ferroportin and/or lipocalin-2. A pool of five mice total RNAs for each condition was used in the experiments. Each two channel chip experiment was done in duplicates with swapped dyes.