Iron acquisition within host cells and the pathogenicity of Leishmania

• Published in: Cellular microbiology Vol. 10; no. 2; pp. 293 - 300
• Main Authors: Huynh, Chau, Andrews, Norma W
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.02.2008; Blackwell Publishing Ltd; Hindawi Limited
• Subjects: Animals; Biological Transport - genetics; Biological Transport - physiology; Cell Membrane - metabolism; Iron - metabolism; Leishmania - genetics; Leishmania - metabolism; Leishmania - pathogenicity; Models, Biological; Proton Pumps - genetics; Proton Pumps - metabolism; Proton Pumps - physiology; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Protozoan Proteins - physiology; Siderophores - metabolism; Siderophores - physiology
• ISSN: 1462-5814; 1462-5822
• DOI: 10.1111/j.1462-5822.2007.01095.x

Iron is an essential cofactor for several enzymes and metabolic pathways, in both microbes and in their eukaryotic hosts. To avoid toxicity, iron acquisition is tightly regulated. This represents a particular challenge for pathogens that reside within the endocytic pathway of mammalian cells, because endosomes and lysosomes are gradually depleted in iron by host transporters. An important player in this process is Nramp1 (Slc11a1), a proton efflux pump that translocates Fe²⁺ and Mn²⁺ ions from macrophage lysosomes/phagolysosomes into the cytosol. Mutations in Nramp1 cause susceptibility to infection with the bacteria Salmonella and Mycobacteria and the protozoan Leishmania, indicating that an available pool of intraphagosomal iron is critical for the intracellular survival and replication of these pathogens. Salmonella and Mycobacteria are known to express iron transporter systems that effectively compete with host transporters for iron. Until recently, however, very little was known about the molecular strategy used by Leishmania for survival in the iron-poor environment of macrophage phagolysosomes. It is now clear that intracellular residence induces Leishmania amazonensis to express LIT1, a ZIP family membrane Fe²⁺ transporter that is required for intracellular growth and virulence.