title: Replication of Neisseria meningitidis within epithelial cells requires TonB-dependent acquisition of host cell iron.
abstract: Neisseria meningitidis (meningococcus [MC]) is able to enter and replicate within epithelial cells. Iron, an essential nutrient for nearly all organisms, is an important determinant in the ability of MC to cause disease; however, its role in MC intracellular replication has not been investigated. We analyzed the growth of MC within the A431 human epithelial cell line and the dependence of this growth on iron uptake. We present evidence here that chelation of iron from infected tissue culture cells with Desferal strongly inhibited intracellular replication of wild-type (wt) MC. We also provide genetic evidence that iron must be acquired by MC from the host cell in order for it to replicate. An hmbR mutant that is unable to use hemoglobin iron and could not grow in tissue culture media without iron supplementation replicated more rapidly within epithelial cells than its wt parent strain. An fbpA mutant that is unable to utilize human transferrin iron or lactoferrin iron replicated normally within cells. In contrast, a tonB mutant could not replicate intracellularly unless infected cultures were supplemented with ferric nitrate. Taken together, these findings strongly suggest that MC intracellular replication requires TonB-dependent uptake of a novel host cell iron source.
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, Oregon 97201, USA. larsonja@ohsu.edu
authors.forename: Jason A
authors.initials: JA
authors.lastname: Larson
authors.forename: Dustin L
authors.initials: DL
authors.lastname: Higashi
authors.forename: Igor
authors.initials: I
authors.lastname: Stojiljkovic
authors.forename: Magdalene
authors.initials: M
authors.lastname: So
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D002478:Cells, Cultured; D002584:Cervix Uteri / Q000166:cytology; D003470:Culture Media; D004847:Epithelial Cells / Q000382:microbiology*; D005260:Female; D005290:Ferric Compounds / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009345:Neisseria meningitidis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D005290:Ferric Compounds; D007502:Iron Chelating Agents; D008565:Membrane Proteins; D009566:Nitrates; D014168:Transferrin; C057616:tonB protein, Bacteria; D007501:Iron; C025302:ferric nitrate