Macrophage iron metabolism and pathologies.
My research focuses on mammalian iron homeostasis and in particular in the key processes of heme iron storage and recycling from aged or damaged red blood cells by macrophages. For this purpose I developed a physiological model that mimics the process of erythrophagocytosis including red blood cells ageing, recognition and engulfment by macrophages. Using this model, we studied the different steps of heme iron recycling by macrophages. (①). We clarified important regulation at both mRNA and protein levels of Ferroportin (FPN), the only mammalian iron exporter identified to date. We also showed that Hepcidin (HAMP), a small peptide considered as the major hormonal regulator of iron homeostasis, induces a rapid internalization and degradation of the macrophage iron exporter present at the cell surface of macrophages. To get insight into the molecular mechanisms involved in HAMP mediated downregulation of FPN protein, we developed cellular and proteomic approaches to better define the environment of FPN in macrophage cellular membranes (②). We studied the relation between macrophage iron recycling, infection with intracellular pathogens (such as salmonella) and anemia of inflammation. (③)
Animal and cellular models:
- Mouse models of iron disorders –(iron overload and iron deficiency)
- Murine Bone marrow derived macrophages
- LCCM (L929 conditioned culture medium to produce M-CSF1) for BMDM culture
- Murine macrophages cell lines : J774a1; Raw264.7
Techniques and methods:
- Rabbit polyclonal antibodies production and purification by affinity
- Protein expression and localization
- Crude membrane versus cytosolic extracts (ultracentrifugation)
- Western blot
- In cell western blotting (Odyssey)
- Immunofluorescence on fixed cells
- Immunohistochemistry and immunohistofluorescence on paraffin tissues section
- In vitro erythrophagocytosis assay (PMID: 16095591)
- In vivo and in vitro salmonella infection